Sculptor David Černý and architect Tomáš Císař from the studio Black n' Arch have designed a 135m ( 450ft)-tall tower for Prague that is shaped like an upended shipwreck and has an observation deck at the top.

Top Tower comprises a conventional high-rise tower with a base section that partially acts as a pedestal for the accompanying sculpture, which takes the form of a sunken ship's skeleton covered in seaweed. The sculpture is not just a visual element, though, but a structural one too.

"The boat is structurally connected to the building," says Tomáš Císař from studio Black n' Arch. "One cannot stand, nor even exist, without the other. Thus the boat is not a mere addition, but rather a fundamental element both intellectually and technically."

While the tower will contain rental housing, offices and space for a multifunctional cultural centre, public visitors will be able to access the viewing deck via a ski lift. Once at the top, they will have 360-degree views of Prague, with landmarks like Prague Castle and the National Theater visible. As Císař explains, there will also be a publicly accessible roof garden.

"The boat becomes a connecting living element between the square, roof garden and viewing points at the highest level. It comprises a notional vertical public space. It is publicly accessible both via the viewing elevator and staircase which link individual height levels, terraces which in future are designed to be used as outdoor galleries and gardens."

Elsewhere, there will be commercial units and underground private and public parking spaces. The 2 billion Kč (US$86m, €78m, £68m)-project also includes the revitalisation of an adjacent pedestrian zone.

Project developer Trigema expects construction of Top Tower to begin in 2021 and take less than three years to complete.