The idea of a canal across southern Sweden was first put forward as early as 1516, by Hans Brask, the bishop of Linköping.

However, since this treaty was mutually rescinded by the United States and Nicaragua in 1970, the idea of another canal in Nicaragua still periodically resurfaces.

The idea of building a canal through Central America is a very old one.

In the 1520s and 1530s, the Spanish crown had ordered surveys of the isthmus to determine the feasibility of such a canal, but the idea was soon abandoned.

The idea of constructing such a canal was first considered by Miles Standish of the Plymouth Colony in 1623, and Pilgrims scouted the low-lying stretch of land between the Manomet and the Scusset rivers for potential routes.

Charles V is credited with the first idea of constructing an American Isthmus canal in Panama as early as 1520.

The alleged motive is that some American business leaders and politicians strongly opposed the negotiations between Torrijos and a group of Japanese businessmen led by Shigeo Nagano, who were promoting the idea of a new, larger, sea-level canal for Panama.

The first known idea to build a canal between the River Mersey and the River Trent was put forward in 1755, though no action was taken at that time.

For local industries along the route of the proposed canal, whose operations relied on water from local rivers and brooks which the canal might also use, its construction was a controversial idea.

The idea for a canal to Liskeard was first investigated in 1777 when Edmund Leach and a gentleman from Liskeard proposed a manure canal, which would be used to transport lime and sand upwards from Looe.

Thomas Telford revived the idea of a ship canal in 1824, which would have taken over the line of the Bridgwater and Taunton Canal – enabling boats to reach the south coast – at a cost of £ 1. 75 million.

However, the idea of turning the canal over to automobiles was opposed by some, including United States Supreme Court Associate Justice William O. Douglas.

Popular response to and press coverage of the hike turned the tide against the parkway idea and, on January 8, 1971, the canal was designated a National Historical Park.

Three Roman rulers considered the idea but all suffered violent deaths ; the historian Suetonius tells us that the Roman dictator Julius Caesar considered digging a canal through the isthmus but was assassinated before he could commence the project.

Eventually, the experience of building long multi-level cuts with their own locks gave rise to the idea of building a " pure " canal, a waterway designed on the basis of where goods needed to go, not where a river happened to be.

The region was suffering from the effects of the Long Depression, and for the canal's proponents, who argued that the scheme would boost competition and create jobs, the idea of a ship canal made sound economic sense.

This work struck de Lesseps's imagination, and gave him the idea of constructing a canal across the African isthmus.

The idea of connecting Dublin to the Shannon was proposed as early as 1715, and in 1757 the Irish Parliament granted Thomas Omer £ 20, 000 to start construction of a canal.

This gave Austrians the idea to dig a canal to connect the Danube with the Black Sea at the shortest point before the Delta, between Rasova or Cernavodă ( Bogaz Köi ) and Constanţa ( Küstendjie ), and a parallel railway.

As the United Principalities of Moldavia and Wallachia ( 1859 ) remained formally Ottoman vassals, and moreover Dobruja was directly administered by the Ottomans, the idea to build the canal was not of interest to Romanians.

The idea to build a canal became a national issue, which could promote Romania's international trade.

Instead, Sage came up with the idea of a canal to float logs from the Black River to supply the mills of Lake Simcoe.

High above the city, near the small town of South Fork, the South Fork Dam was originally built between 1838 and 1853 by the Commonwealth of Pennsylvania as part of a canal system to be used as a reservoir for a canal basin in Johnstown.

With the coming-of-age of railroads superseding canal barge transport, the lake was abandoned by the Commonwealth, sold to the Pennsylvania Railroad, and sold again to private interests and eventually came to be owned by the South Fork Fishing and Hunting Club in 1881.

At first there was no passenger service, for south of the station was the Akihabara cargo docks, where goods from all over the world would flow into Kanda by river and be hauled up the east bank of the canal to be ticketed at the central cargo transport window.

Later, navigation was stopped in 1904 and the canal has since then, been exclusively used for irrigation purposes only.

At present the canal does not flow in district Gurgaon, but only in Faridabad, which was earlier a part of Gurgaon.

In other cases, water pumped from mines was used to feed the canal.

By far the longest canal was the Grand Canal of China, still the longest canal in the world today, and the oldest extant one.

The project began in 605 and was completed in 609, although much of the work combined older canals, the oldest section of the canal existing since at least 486 BC.

The first artificial canal in Christian Europe was the Fossa Carolina built at the end of the 8th century under personal supervision of Charlemagne.

It was constructed in 1639 to provide water power for mills. In Russia, the Volga-Baltic Waterway, a nationwide canal system connecting the Baltic and Caspian seas via the Neva and Volga rivers, was opened in 1718.

The most notable power canal was built in 1862 for the Niagara Falls Hydraulic Power and Manufacturing Company.

In France, a steady linking of all the river systems — Rhine, Rhône, Saône and Seine — and the North Sea was boosted in 1879 by the establishment of the Freycinet gauge, which specified the minimum size of locks so that canal traffic doubled in the first decades of the 20th century.

Among these was a large canal leading from the Rhine to the sea, as well as a road from Italy to Germany — both begun by his father, Drusus.

The canal was featured on Ripley's Believe It or Not in the 1970s due to the phenomenon that in winter the canal freezes before the lakes and then after the lakes freeze, the canal thaws and remains unfrozen for the rest of the winter.

In their first major use at the Battle of Cambrai ( 1917 ), the plan was for a cavalry division to follow behind the tanks, however they were not able to cross a canal because a tank had broken the only bridge.

The canal was mooted in classical times and an abortive effort was made to build it in the 1st century AD.

In the 19th century, it was connected by a canal to the Berezina and Dnieper rivers ( canal is currently not functioning ).

Another proposal for a canal northwards to the Trent at Burton was actively discussed between 1791 and 1793.

A project is currently being discussed in Russia to destroy the rapids at Losevo and turn the River Burnaya, Lake Sukhodolskoye and lower portions of Vuoksi into a navigable canal, which would connect Lake Ladoga to the Gulf of Finland and allow oil tankers to bypass River Neva and the city of Saint Petersburg.

As early as 1787, George Washington and Thomas Jefferson had discussed the desirability of a canal linking Lake Erie to the Ohio River as part of a national system of canals.

In that year, proposals for a new canal between the Oakham Canal at Oakham and the Stamford Canal at Stamford, which had been discussed in 1785, were revived, as part of a larger plan for a link from Stamford to the River Nene at Peterborough, and a connection from near Market Deeping, where the Stamford Canal rejoined the River Welland, northwards to the South Forty-Foot Drain.

There, they discussed the problems of funding the building of the canal, and need for a place of worship for the large Protestant following in Bytown.