It is hard to walk through Venice, Italy without wondering how the place was built, its architecture rising inexplicably out of the dark water below, or how water, power and internet traverse its myriad canals. The Rialto Bridge is a great place to begin unpacking these mysteries.

Making this bridge possible is a forest of over 12,000 tree trunks burrowing below the surface. Dating back centuries, these foundations are embedded through loose soil below the waterline and into solid clay below, and support over 10,000 tons worth of structure above.

The whole city sits on over 10,000,000 tree trunks. The wood doesn’t rot because the poles are protected by surrounding mud, away from oxygen that would lead to decay.

Meanwhile, bridges like the Rialto serve a function beyond just connecting people — they also help water and utilities flow around the city, without needing to burrow underground or displace space in shallow canals.

The city still faces threats from structural decay, sinking structures and rising water levels, but perhaps the most amazing thing is that it is still standing at all hundreds of years after it was built.