Longarone, Italy travel guide: The town wiped out by an 'inland tsunami'

Dark history exists in many places – wars, natural disasters, evidence of human greed, immorality and venality. Some places choose to forget. Longarone in Italy's northern Dolomites chooses to remember. How could it not? About the time of President John Kennedy's assassination, the entire town, along with four others, was destroyed by a man-made megatsunami that killed about 2000 people, 1400 from Longarone alone.

The Alpine town 100 kilometres from Venice, set between jagged needle peaks, is a memorial to human resilience. It is beautiful again, rebuilt, set in the long valley of the Piave River facing the mountain that brought disaster.

There are "places of memory" everywhere you go in Longarone: the memorial church designed by eminent 20th-century Italian artist Giovanni Michelucci, the Museum Longarone Vajont's "Attimi di Storia" (moments of history), the Vajont memorial graveyard at nearby Fortogna, the garden of solidarity and the square of the monumental church where people may gaze directly across the valley to Mount Toc. The museum is a mandatory destination for all who visit Longarone. It details "a tragic tale about water."

At 10.39pm on October 9, 1963, as people slept or prepared for bed, there was a "roar and then the silence of death" as a section of the mountain the size of a small village broke away – the largest landslide ever recorded in Europe. It dumped 260 million cubic metres of earth, rock and forest into the deep and narrow Vajont Dam, the world's highest double-curvature arch dam at 262 metres, which was being built to generate hydroelectric power for the country's northern industrial cities.

The dam was built despite authorities knowing this was an area of unstable geology, prone to earthquakes. They even charged an investigative journalist with "diffusing false and biased news in order to disrupt the public order".

The displaced 50 million cubic metres of water rose in a 240-metre-high tsunami and burst 100 metres over the dam wall into the Piave Valley below. It took four minutes for the wave, estimated to contain twice the energy of Hiroshima's atomic bomb, to flatten the valley. The water was so powerful that the victims were mostly found naked, their clothes ripped off by the blast.

The water left a crater 60 metres deep and 80 metres across on the valley floor. The now unused dam, which remained intact, is open for visits. We have ridden in to Longarone on the Pieve di Cadore to Belluno leg of our 350-kilometre cycle from the Dolomites to the Adriatic Sea. The town demands you linger to consider the folly that placed "progress" above human beings.