If you've never been, you should visit the Emerald Buddha temple and the royal palace and the national museum nearby. But personally, I like more Wat Saket (the temple of the golden mountain) and the view from the mountain itself Also very cool Wat Arun, especially its amazing pagoda, worth a visit. Basically there are many more temples, some you can visit on the way, for example if you get to Asiatique. Which I highly recommend. Firstly, one way from or to Saphan Taksin BTS station you can take a free river boat from Asiatique, or a longtail or a pleasure boat, I strongly recommend to do it at sunset, the view on Chaopraya is gorgeous. Secondly, there are some nice temples on the way if you walk from the station to Asiatique. Finally, in Asiatique you can eat at an atmospheric seafood restaurant, buy some swag, eat some cool ice cream, walk along an excellent promenade, even ride the Ferris wheel. Of course out of the parks I advise you Lumpini, as it is in the center, you can walk somewhere along the road. In the evening you can visit Kaosan Road, a shopping street - a perpetual find-market. If you want an observation deck, first of all you can visit Bayok Sky - the 83rd floor has a good view It's best to go not very early, but in the morning while there are no crowds. Secondly, the skywalk is a glass-floored observation deck at King Power Mahanakhon. Also, they say it's nice to sit in Cloud 47 - bar and observation room at the same time, but I was not there, I will go there Of interest is the Jim Thompson house-museum, architecturally beautiful and an interesting exposition. The Erawan Museum is interesting - a giant three-headed elephant and cool inside, but a bit far from the center. You can visit Sea Life Bangkok - the aquarium, I like it a lot, you can stay there for a long time .
Also very cool Wat Arun, especially its amazing pagoda, worth a visit. Basically there are many more temples, some you can visit on the way, for example if you get to Asiatique. Which I highly recommend. Firstly, one way from or to Saphan Taksin BTS station you can take a free river boat from Asiatique, or a longtail or a pleasure boat, I strongly recommend to do it at sunset, the view on Chaopraya is gorgeous. Secondly, there are some nice temples on the way if you walk from the station to Asiatique. Finally, in Asiatique you can eat at an atmospheric seafood restaurant, buy some swag, eat some cool ice cream, walk along an excellent promenade, even ride the Ferris wheel. Of course out of the parks I advise you Lumpini, as it is in the center, you can walk somewhere along the road. In the evening you can visit Kaosan Road, a shopping street - a perpetual find-market. If you want an observation deck, first of all you can visit Bayok Sky - the 83rd floor has a good view