Parthenon in Municipality of Athens

You're standing at the Parthenon, the temple of Athena on the Acropolis of Athens. Start with the columns. There are eight at the front and back instead of the usual six, and forty-six run all the way around. They're about ten metres tall and swell slightly in the middle. They also lean a little inward, and the floor rises by up to about eleven centimetres towards the centre. All clever tricks to make the building look perfectly straight from a distance.