To reach the top of the tower, there is an external double-helix staircase, or visitors can take the elevator with two buttons. The EchoPark Automotive Grand Prix race is scheduled for Sunday ...

The commercial centre's centrepiece is the double-helix staircase, which spirals from the ground floor and punctures through the metal roof to rise to a viewpoint looking out to the distant ...

Designed originally as a hunting lodge for François I, Château de Chambord boasts a double-helix staircase, the design of which has been attributed to Leonardo da Vinci. The two spirals never meet, ...