By Laura Smith-Spark
Nicaragua's ambitious plans to build a new inter-oceanic waterway to rival the Panama Canal are making waves within the isthmus.
Could Lake Nicaragua become a transit route for super-tankers?
The proposal was publicised ahead of Panama's referendum which on Sunday backed a $5bn project to enlarge its own canal.
Opinion is divided on whether Nicaragua's $18bn canal project represents an unrealisable pipe dream - or a grand design from which one of the world's poorest countries will reap huge rewards.
History presents plenty of examples of projects first dismissed as unworkable, but then revived when new technology, funding or political will came into play.
Among them are the Suez, Corinth and Panama canals, the Channel Tunnel - first proposed two centuries ago - and the rail tunnel under the Bosphorus, to name a few.
But, architects warn, there are also plenty of failed schemes and white elephants littering the planet - many at great cost to the taxpayer.
Just this month, Italy dropped plans to build the world's longest suspension bridge, across the Straits of Messina to Sicily - on the drawing board since the 1960s - on the grounds the money could be better spent elsewhere.
This is certainly not the first time that Nicaragua has heard proposals for a canal linking the Atlantic and Pacific Oceans.
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The idea was first mooted by Spanish explorers five centuries ago - and was seriously considered in the 19th Century, before the US opted to back the Panama Canal instead.
According to shipping expert Marc Hershman, of the School of Marine Affairs in Seattle, the chances of Nicaragua's plans coming to fruition now are probably greater than ever before.
"There's tremendous growth in demand for cargo shipping around the world and all along the west coast of America," he says.
"Even if it's still a dream, it's less of one than it was a while ago."
But he points to Nicaragua's need for huge international financial backing, both public and private sector, as the major stumbling block for the project.
Critics have also questioned President Enrique Bolanos's assertion that the 277km-long (173 miles) canal could be built in 12 years, and raised concerns over the cost to the environment and Nicaragua's indigenous people.
According to Paul Finch, editor of the London-based Architectural Review magazine, grand designs fall into two categories.
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The first - such as the Suez Canal - covers those projects undertaken because their backers believe they stand to make a fortune.
The second "is where it's really a symbolic statement about the significance or importance of a country or a president".
He cites the example of the Cathedral of Christ the Saviour in Moscow, originally built in the 19th Century at the behest of Tsar Alexander I.
In the 1930s it was demolished on the orders of Stalin, who intended a towering skyscraper - the Palace of Soviets - to be built in its place, topped by a 100m-tall statue of Lenin.
However, World War II intervened and the plans were shelved; instead, in the 1950s, a giant outdoor swimming pool was built.
Finally, in the 1990s, Moscow's Mayor Yuri Luzhkov led a project to restore the cathedral. Its rapid and costly reconstruction was seen by some as a symbol of Russia's spiritual revival after the Soviet era - by others as a product of the mayor's own ego.
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Newly emerging nations have a particular weakness for status-driven schemes - such as building new national airports - which later prove to be white elephants, Mr Finch says.
However, developed nations like the UK are also guilty of embarking on projects motivated by "a desire to fill a gap" rather than actual need.
He suggests the Humber Bridge - "an inspired project to link two parts of England that didn't need to be linked" - the Channel Tunnel and Heathrow's Terminal Five as falling under that umbrella.
Madness or vision?
Proponents of the Nicaragua plan have already been at pains to stress that their canal will meet a real need - that of the new breed of super-tankers too large to fit through even a widened Panama waterway.
One proposed route would take the canal up the San Juan river that forms a border with Costa Rica to the south, across the huge Lake Nicaragua and out to the Pacific Ocean at San Juan del Sur.
Other river routes, as well as a coast-to-coast railway, have also been put forward.
Whether the benefits would end up outweighing the cost - particularly for the general public - remains to be seen.
And history suggests it is cost-effectiveness that ultimately decides whether grand designs are judged madness or visionary, says Professor Sir Peter Hall, of The Bartlett School of Architecture and Planning, University College London.
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"Some of them, like the Panama and Suez Canals, changed the world because they were waiting to happen and would have happened anyway," he says.
"There are other schemes, like the plan to link Sicily to the Italian mainland... that are probably good ideas in principle but the question is whether they stack up in terms of demand.
"It all comes down to commercial viability - whether they succeed depends on whether they can be expected to pay their own way."