Hagia Sophia

Hagia Sophia is the one building in Istanbul that everyone knows by name, and standing inside it is one of those travel moments that lives with you. The current structure was completed in 537 CE under Emperor Justinian, who at the inauguration reportedly cried out "Solomon, I have surpassed you!" — a boast that, looking up at the 31-meter central dome, still feels earned fifteen centuries later.

It served as the world's largest cathedral for nearly a thousand years, then as a mosque for nearly 500, then as a museum for 80, and in 2020 it returned to being a mosque. The result is a layered space: Byzantine marble floors, Ottoman calligraphy roundels, Christian mosaics of the Virgin and Child peeking out from behind plaster that was once whitewashed over. You'll see Muslim faithful praying on the upper gallery floor while tourists below photograph the same dome they photographed as kids.

The queues can be brutal. Come at opening (09:00) or after 16:00. Dress modestly — headscarves for women are provided at the entrance. Photography is fine; tripods are not.