As any local knows, Venice is an upside-down forest. The city, which turned 1604 years old on March 25, is built on the foundations of millions of short wooden piles, pounded in the ground with their tip facing downwards. These trees – larch, oak, alder, pine, spruce and elm of a length ranging between 3.5m (11.5ft) to less than 1m (3ft)  – have been holding up stone palazzos and tall belltowers for centuries, in a true marvel of engineering leveraging the forces of physics and nature… The Venetian piles technique is fascinating for its geometry, its centuries-old resilience, and for its sheer scale. No-one is exactly sure how many millions of piles there are under the city, but there are 14,000 tightly packed wooden poles in the foundations of the Rialto bridge alone, and 10,000 oak trees under the San Marco Basilica, which was built in 832AD.