Calton Hill in Edinburgh. This is the unfinished National Monument of Scotland. Initiated in 1816, a year after Napoleon's defeat at Waterloo, the monument was meant to be a replica of the Parthenon in Athens, as a memorial to those who had died in the Napoleonic Wars. Building began in 1822, but funds ran dry by 1829, and only a facade of the building was completed. It was dubbed "Edinburgh's shame", but it's now a popular landmark and it's a lot of fun crawling up and down its giant steps.