Join this mind-boggling quest around some of the world's greatest buildings, following the clues with famous artist Stephen Biesty.

A mysterious postcard arrives at Stephen's home. It contains a clue to an incredible quest for treasure. Somewhere in the world there's a lost city of gold: and you can help find it!

Join Stephen for a whirlwind dash around the globe to track down the secrets of the most famous buildings in history. You'll find messages in invisible ink, maps, code breaking notes and more to help you. Plus, thanks to Stephen's fantastic `inside-out' drawings, you'll get an amazing view of the nooks and crannies of each site and find out what they were like in their heyday.

From the Empire State Building to the Colosseum, the Sydney Opera House to Angkor Wat: solve the clues, crack the codes, answer the riddles, and discover who the mystery postcard writer is.