Sweden Stockholm City Station (Commuter Rail Station)

This station is called "Stockholm City Station" and is located on the Stockholm City Line. The station is technically not part of Stockholm's metro system, but it is accessible by foot from the metro station "T-Centralen". The station opened in 2017.
Stockholm’s metro is the world’s longest art exhibition because nearly all of its 100 stations are designed by artists. So buying a ticket for public transport is like buying a ticket for a museum.

You should avoid the peak hours and visit this station at night.
Tripods are officially not allowed, so clarify that beforehand with the operator (SL). If you do use a tripod, you should take multiple exposures for maximum dynamic range (bracketing).

Stockholm Central Station (railway station), T-Centralen (metro station) and Stockholm City Station (commuter rail station) are on different levels, but they are all connected to each other.
You need a valid ticket to get to any platform in the system. So why not use it to get around as well?
You do not need to buy an extra ticket for the Stockholm City Line just to get to the escalators and platforms if you travel by metro.