The challenge of undertaking the £1 billion transformation of London Bridge Station while keeping it open. Las Vegas' most outrageous building. Singapore's Gardens by the Bay.

A towering bridge in France, an 'upside-down' hotel in China, and a 'forest into the sky' in Italy, and finding out how they were built.

Three gravity-defying structures, from an alien port authority in Belgium to an ultrathin skyscraper in Manhattan and a 'hanging' museum in Scotland.

The inside stories behind a new, horseshoe-shaped complex in Rotterdam, a rock-shaped opera house in China, and a makeover of the British Museum.