This structure is so cool. It is so cool that I might even classify it as my favorite site-to-see in Rome. This temple was built in 126 AD. Folks, this is a very old building. And what is even more impressive considering its age, the Pantheon's dome is still one of the worlds largest domes. And what is even cooler than all of that, the dome has a giant hole in the center of it. They say that despite the hole, it never rains in the Pantheon (and the undamaged marble floor seems to confirm this). Hot air rises up through the structure pushing rain clouds away. Uh-mazing.