Do yourself a favour and buy a ticket online to skip the lines. This place is definitely worth seeing, but the crowds are intense. Allow sufficient time to see everything.
At 44 hectares and with a population of 1000, this is the smallest country on Earth.
Construction on the Basilica began in 1506 and was completed in 1626. Make sure you get in early to beat the crowds.
The Vatican Museums have quite an impressive collection, but the most stunning things you will see are the paintings on the walls and ceilings. The Sistine Chapel and the Raphael Rooms are definitely highlights.