Stonehenge, Britain's greatest icon, symbolising mystery, power and endurance. The Taj Mahal, which bankrupted an empire in the name of love, and the Eiffel Tower, the first structure to surpass the height of the Great Pyramid of Cheops. Through monuments we learn about history, culture, the rise and fall of civilizations - for example, that to create the giant stone figures of Easter Island, up to 20,000 natives must have lived there before denuding the island's rain forests and disappearing. Or that the bridges and canals of historic Amsterdam actually connect ninety man-made islands, making the city of merchants one giant dock and warehouse.