If you are interested in architecture and engineering, Bhumibol Bridge is worth seeing on a trip to Bangkok.
It crosses the Chao Phraya River in the industrial south of the city, linking Bangkok with Samut Prakan province, and it is especially photogenic at night. The industrial part of Bangkok is an interesting area to explore, away from the usual tourist sights.
More about Bhumibol Bridge
Bhumibol Bridge was a royal project initiated by King Bhumibol Adulyadej (Rama IX) to ease traffic in Bangkok and the surrounding area. Apart from its interesting architecture, it has a scenic view, especially at night.
The bridge, also known as the Industrial Ring Road Bridge, crosses the Chao Phraya River twice. It has two striking cable-stayed spans supported by diamond-shaped pylons. The northern bridge, Bhumibol 1, connects Yan Nawa district in Bangkok with Phra Pradaeng district and stands 50m above the river. The second, Bhumibol 2, has much the same structure.