They all laughed at Christopher Columbus, when he said the earth was round. They all laughed when Edison recorded sound. They all laughed in 2002 when Bertrand Delanoë unveiled plans for a temporary urban beach on the Right Bank expressway in central Paris - but haw-he-haw, mes amis - who's got the last laugh now?
The answer, of course, is the chic citizens of the city of light, as the Paris Plage gears up for its eighth successful summer.
The first Socialist mayor of Paris may receive more press nowadays for his bikes than his beach, but the Plage is still thriving. Four million Parisiens will flock to the Seine this summer for sand, deckchairs, palms and parasols.
Happily, Amsterdam also has its own Plage - open all summer - as well a huge roof terrace, a natural inland beach, and of course the actual beaches at Zandvoort and Bloemendaal aan Zee nearby.
Apparently we're also trying one in Blighty: it's in sunny Nottingham. Hmm, let me get back to you.
While the tone of the Plages is likely to be city grit rather than timeless elegance, they are a great trend – and with tourists making up just 15% of the clientele at the Paris Plage, one that clearly meets with local approval. Come on Boris, get involved.