Si Lom MRT Station

The main reason you'll end up here is the interchange. This is where the MRT Blue Line meets the BTS Silom Line at Sala Daeng, and if you're on a BTS day pass heading for Chinatown and Wat Mangkon, this is your switch. Fares are separate, so you'll need an MRT card or a single-journey token from the machines. The token comes back to you at the end of the ride, which catches out first-timers.

Beyond that, it's a useful piece of infrastructure in its own right. The multi-level layout under the road means you can surface near Lumphini Park, Central Park mall or the Dusit Thani without playing chicken with Bang Rak traffic. It's air-conditioned, clean, the restrooms work, and there are stalls if you want a snack before you get on. Signage runs in Thai and English, so finding the right platform isn't a puzzle.