Explore Lumpini Park
The Royal Elephant Museum
Visit the Chatuchak Weekend Market
Temple hop
Hang out on Khao San Road
Bangkok is full of history, temples, and Thai ruins. There are about 10 main temples in the city, and you can easily just hire a guy to take you to all of them in one day. They are all have different architecture and layouts. It will take about five hours to see them all.