Tokyo Skytree

The tower is six hundred and thirty-four metres — a figure chosen because it reads mu-sa-shi in Japanese, the old name of the region. It was built because Tokyo's skyscrapers were blocking the television signal from Tokyo Tower, a third of its height.

Its earthquake structure copies that of wooden pagodas: a central concrete column, decoupled from the frame, which sways out of phase and damps the movement. No five-storey pagoda has ever fallen in an earthquake in Japan, and the tower's engineering starts from that observation.