Jerónimos Monastery

Built with "spice money" from Portuguese discoveries, this monastery took 100 years to complete - talk about a long-term project! King Manuel I built it to honor Vasco da Gama's successful trip to India and even gave it the monks' order that had been praying for his safe return. Inside lies Vasco da Gama himself, along with poet Luís de Camões, who wrote Portugal's national epic while losing an eye in battle (and allegedly swimming with his manuscript held above water). Look closely at the cloisters - each column is uniquely carved with coral, ropes, and monsters that sailors swore they saw at sea. (Tip: the queue can be huge, but if you buy a ticket at the Archaeological Museum next door, you can skip the line.)