The above mentioned places by Richard and Jennifer are amazing ,for whoever loves nature. As for Bangkok I didn't like it much. You could it say it has beautiful places to visit , but not the most beautiful at all.

Visiting the hill tribes in Chiang Mai is amazing.

The ocean, the beaches and the scenary are beautiful in Koh Samui and Phuket...

Pattaya was beautiful when I went there in 1980. I have not been to Bangkok.