The Temple of Olympian Zeus in Athens, Greece, is a colossal ancient temple dedicated to the king of the gods. Construction started in the 6th century BC but was not finished until over six centuries later by Roman Emperor Hadrian.
Despite its grandeur, the temple fell into disrepair and was pillaged, leaving only 15 standing columns today. It is now an open-air museum where you can soak up some serious historical vibes while wandering around the ruins.