The important economic and strategic position of Ancient Corinth, as it was located in the Peloponnese, on the narrow strip of land between the Saronic and Corinthian Gulfs, made it a powerful and wealthy city, but also a particularly prosperous naval power.

Its power increased even more when Periander (627-585 BC), one of the seven wise men of the ancient world, took power.

Periander was the first to try to unite the two seas, but he met with great opposition from the priesthood and merchants of the time, with the excuse that this would provoke the wrath of the gods, based on an oracle of Pythia that supposedly said "Isthmon, do not tower nor mine, Zeus gar has been an island or a bull".

In reality, of course, the only thing that worried the religious and financial establishment of the time was the loss of income it would have from travelers, who would no longer have a reason to stay in Corinth and spend money on food, gifts and offerings to the temples, but would simply pass through the city.

However, Periander does not seem to have been intimidated by these reactions and attempted to proceed with the construction of the project.  However, due to the enormous technical difficulties that arose due to the hard rocks, which resulted in a long delay in the progress of the works, which was artificially attributed to the wrath of the gods, but also due to the fierce desire of the inhabitants for Corinth to maintain its privileged position as a "keyholder" of transit trade in the Mediterranean region, The project did not go ahead.

Thus, Periander, instead of a canal, built Diolkos, a paved road, which served to transport ships from one side of the Isthmus to the other, using the power of slaves and animals.

The duties imposed on goods were so many and the wealth that flowed into the city of Ancient Corinth was so great that it is said that Periander ceased imposing any other kind of tax on the Corinthians.

Diolkos was a road, constructed serpentinely due to the altitude difference, paved with large porous blocks, connecting Posidonia (Corinthian Gulf) with the beach of Schinounta (Saronic Gulf). Its width was variable, 3.5 – 5 meters, and deep parallel grooves were carved along its entire length, at a distance of 1.5 meters, to facilitate the movement of the wheels of the vehicle and avoid overturning.

Up there was the "whole youth", a wheeled vehicle, which dragged the ships and carried them from one sea to another. The ships no longer had to circumnavigate the Peloponnese, thus gaining a journey of about three weeks, but also avoiding adverse weather conditions.

The ships, in order to pass through the Isthmus, were super-distributed, from one sea to another, without their goods. That is, when a ship arrived at the port of Lechaion in the Gulf of Corinth or Kenchrea in the Saronic Gulf, it was unloaded from the goods, supported on wooden cylinders and on the "olkos", probably pulled by animals or slaves, and when the "olkos" reached the other end of the Diolkos, the ship was thrown back into the sea and, After loading it with the goods that had already been transported by land in carriages, it continued its journey.

Unfortunately, from the parts of the cobblestone brought to light by the excavations we do not have sufficient information whether Diolkos served the passage of merchant or warships. Most likely, both categories were served, since Thucydides is informed that it was possible to use Diolkos to transport a trireme (a fast ancient rowing warship).

Of course, for this "passage" the ships paid very expensive fees (tolls), which was the most important income of Corinth.

Diolkos was in use until the 12th century AD.

Demetrius the Besieger in 307 BC, three centuries after Periander's attempt, also attempted to cut the Isthmus of Corinth, to no avail. The reason is the assurance of Egyptian engineers that the waters of the Corinthian Gulf will drown the islands of the Saronic Gulf, due to the difference in water levels.

During Roman times, Julius Caesar (44 BC) and Caligula (37 BC) made similar plans, but for political and military reasons they never materialized.

The first serious attempt was made by Nero in 67 AD. Nero was only 29 years old and during a visit to the region to observe the games of the Isthmian Games he made the decision to proceed with the opening of the canal, based on the plans of the previous ones.

He even inaugurated the excavation work himself, using a golden pickaxe, and ordered the construction and placement of a commemorative plaque on the wall of the canal depicting his figure.

With the hard and obligatory labor of 6,000 Judean slaves and convicts, excavation work had progressed 3,300 meters long and the work looked like it could be completed. However, work was interrupted when Nero, having been forced to return to Rome to face the revolt of General Galba, was assassinated shortly afterwards (68 AD).

How serious and studied Nero's effort was is proved by the fact that during the final opening of the canal, in modern times (19th century), not only were 26 test wells found, each 10 meters deep, as well as various trenches of his time, but the same alignment that was then designed was chosen as the most correct and economical.

Nero's "successors" in the grandiose plan of opening the Isthmus were Herod Atticus, then the Byzantines and, finally, the Venetians, but for various reasons all of them failed.

The newly established Greek state, emerging from Ottoman rule, found itself on the threshold of the industrial age, weakened economically and without modern infrastructure. 

In 1830, the first governor, Ioannis Kapodistrias, foreseeing the great importance that the construction of the canal would have for the development of the country in general, assigned the relevant study to the special French engineer Pierre Théodore Virlet d’Aoust. However, the sum of 40 million gold francs, which, according to the expenditure budget, was deemed necessary for the implementation of the project, could not be found by the international financial market, let alone made available from the Greek budget, so the idea was abandoned.

A few years later, the operation of the Suez Canal (1869) mobilized again the then Greek government, since the conditions of international trade and shipping in the Mediterranean made the realization of the project necessary and the route through the Isthmus provided two important advantages, safety and economy, to international shipping, while at the same time bypassing the dangerous capes of Cape Malea and Cape Matapa would not only reduce the risks of maritime accidents. but also transport costs (time, fuel, insurance premiums).

Thus, the Zaimi government, in November 1869, passed the law "on the drilling of the Isthmus of Corinth". By this law, the government had the right to grant to a company or individual the privilege of constructing and operating the Corinth Canal.

To this end, in 1870 a contract was signed with French businessmen, which, however, languished. In 1882 it became possible to establish the “International Company of the Sea Canal of Corinth” by the Hungarian General István Türr (1825-1908), to whom the Greek State a year earlier had awarded the project, with the privilege of exploiting it for 99 years.

The company was formed with the assistance of a French bank and the share capital consisted of 60,000 shares of 500 francs each.

Thus, on April 22, 1882, in the presence of King George I and many dignitaries, work began on the section of the Isthmus.

The project was designed by the Hungarian Béla Gerster (1850–1923), Chief Engineer of the Francis Canal in Hungary, and checked by engineer Vincent Dauzats, Chief Engineer of the Suez Canal, collaborator of Ferdinand de Lesseps.

Architects and engineers from all over Europe collaborated for its realization and used prototype explosive devices, dynamite and other explosives from the Nobel family's factories in Italy and Germany. But the project was again halted after about eight years, due to Tyrr's bankruptcy. In 1890 the effort was continued by the Greek Contractors Company with the participation of Andreas Syngros (1830-1899).

The Canal was finally handed over to shipping in 1893, after 11 years of work.

On 25/7/1893, in the presence of the Kings, the Government, a large number of people and officiating the Metropolitan of Corinth, the inauguration of the Canal took place and Queen Olga cuts the ribbon with golden scissors, as the first ship passes, in a festive and enthusiastic atmosphere.

The project was one of the most important public works programs that took place in the late 19th century and was associated with the person of the modernizing Prime Minister Charilaos Trikoupis.

The total volume of soil mined for the construction of the Canal reached 12 million cubic meters.

• The Canal has a direction of 131.5o - 311.5o and intersects in a straight line the Isthmus of Corinth.

• Intersects the rough terrain of the Isthmus up to 79 meters above sea level.

• The total length of the Canal amounts to 6,343 meters, of which 540 meters are occupied by the ports of Isthmia and Posidonia.

• The starting point of measurement is located on the axis of the Canal at a fixed point 83 meters from the jetties of Posidonia and ends at a point of the axis 40 meters from the breakwater of Isthmia.

• The maximum safe width of the Canal for navigation is 24.60 meters at sea level and 21 meters at the seabed. The depth of the Canal is 8 meters.

• The maximum safe height of the Canal for navigation is limited to 52 meters due to the railway and road bridge.

• The Canal is lined with stonework for most of its length from the seabed up to two meters above sea level.

• The geological composition of the slopes of the Canal is uneven, with a variety of geological composition of soils -mainly marl and sandstone-, cut by dozens of faults in the direction from East to West and with an acute angle relative to the axis of the Canal.

• In some places the Canal is widened due to falls, which have been caused by earthquakes, war events during World War II, as well as soil erosion.

• The winds prevailing in the Canal are mainly northwestern, followed by east and south. Sometimes there are also northerly winds of high varying intensity, which require special attention for the entry and exit of ships on the Posidonia side.

• Sea currents in the Canal usually change direction every six hours.

• The usual current speed is two and a half (2½) knots and rarely exceeds three (3) knots.

• When changing the direction of currents, the stagnation of water is noticeable, while its speed in the opposite direction gradually increases.

• External factors, such as tidal events and winds, which blow in a constant direction for days, can affect the period of current rotation.

• The difference between the highest level and the lowest sea level in the Canal reaches sixty (60) centimeters.

• The Canal operates 24 hours, 7 days a week except every Tuesday from 06:00 to 18:00 when routine maintenance works are carried out.

Perama – Submersible Bridges

In order to serve the movement of residents and vehicles from Sterea to Peloponnese and vice versa, two passages operated, one in Posidonia and one in Isthmia from 1893 until 1986 when they were replaced with the Submersible Bridges that operate until today. Perama was a floating raft that operated with chains, a fixed chain on one side of the passage where it held it in the correct position, while the other chain on the other side pulled it to sail. When a vessel passed through the canal, they let the chains sink for the free navigation of passing ships. From 1960 to 1980 motors were used for the operation of the passage, while in the past the whole process was done manually.

The passage of Isthmia could carry one car and about 10 people, while the equivalent of Posidonia, which was larger, carried two cars and about 20 people. The journey took about five minutes and the routes were continuous (every 5-6 minutes).

The two submersible bridges replaced Perama at the ends of the Canal, one to the Saronic Gulf and the other to the Corinthian Gulf. Their resting position is in the upper position and they sink when a ship is about to pass. Their operation is 24 hours a day and the operation is done by one operator every 8 hours.

The Posidonia Bridge is located towards the Corinthian Gulf was built in 1985 and serves mainly the movements of the residents of Corinth and Loutraki, the Isthmia Bridge is located towards the Saronic Gulf was built in 1987 and serves the movements of the residents of Isthmia. The two bridges are the same in terms of electromechanical part and differ only in pedestals.

The Battle of the Corinth Canal refers to the German invasion of Greece on April 6, 1941, where Allied forces pushed back toward Macedonia and Thessaly from mainland Greece, while the British fleet stood at various ports in southern Greece to evacuate any remaining Allied troops from advancing German ground and air units. A crucial target during the German invasion was the Corinth Canal separating the Peloponnese from the Greek mainland, as Hitler saw it as a gateway to control the Aegean Sea and trap retreating Allied forces in Greece if it could be captured and kept operational.

The German attack on the Corinth Canal was given the name Operation Hannibal with the main objective of the operation being the Corinth Canal. German forces felt that if the bridge could be captured and held, the planned evacuation of the Allies to either Crete or Egypt would be delayed, if not stopped completely. However, the bridge itself was held and defended by British and Australian troops and was wired for destruction in order to block the canal.

A major interruption of the operation of the Canal took place in 1944, due to the blowing up of the slopes caused by the Germans when they left. At that time, a volume of 60,000 cubic meters of soil collapsed, and the excavation works lasted 5 years (1944-1949). It should be noted that, before the explosion, the Germans threw a significant number of railway vehicles into the Canal, in order to complicate the task of expression.

The Corinth Canal is an international maritime transport hub.  It is the shortest and safest sea route for ships coming from the ports of the Ionian Sea, the Adriatic Sea, Southern Italy and for ships crossing the Strait of Messina and heading to ports in the Eastern Mediterranean, up to the Black Sea and vice versa.

During the crossing of the Canal users can enjoy:

• The straight section of the Isthmus with a total length of 6,343m, which created a sea route at a depth of up to 78 meters from the earth's surface,

• The natural slopes of the Canal of particular natural beauty and geological interest,

• The plaque of Nero, emperor of Rome and one of the implementers of the opening of the Canal,

• The western part of ancient Diolkos, a paved road used in antiquity for the transport of ships by land.