Bangkok is the largest- and Capital city of Thailand.
Khao San Road is one of the most famous streets in Bangkok. At nighttime they make it to a walking street, and it's just pure partying there.
One of my highlights was definitely to go to the top of King Power Mahanakhon. The Tower is the highest Building in Bangkok and looks truly amazing.
For 500 baht, an elevator takes you to the very top, and you can use your 500 Baht entry fee as a voucher at the Rooftop bar.
Another spectacular thing up there is, you can enter a balcony whose floor is made of glass, so you can look 314m down below your feet. Which is a bit scary but really cool and definitely a good spot to take a picture.