La Sagrada di Familia, Barcelona, Spain
Hagia Sophia, Istanbul, Turkey
The Pantheon, Rome, ItalyThis is my favorite building in the world so far. If you sit on the floor in the middle and put your face by the ground, you can see that the ground near the walls is significantly lower. This is because the walls are ten feet thick and over hundreds of years they’ve actually sunk into the ground.
The Great Rucksack Revolution 