My family and I climbed Michaelangelo's dome at St Peter's basilica in Vatican City and I got a decent photo from the square from the top. The Pope does his speeches from the balcony just below me. (Well, below that line of statues in front of me)

Honestly, nothing prepared me for just how big the Roman Colosseum is. They guess it held about 40k people but walking through it was like walking through a small modern baseball stadium, except it was built over 1,000 years ago.