Most of the time in various ST series, they are traveling to planets or at least star systems to locations there. Certainly there are space stations and the like, but these all appear to be orbiting stars or planets. Are there any locations in Star Trek that are visited regularly but are not specifically part of a star system?
EDIT: It seems that the difficulty of this question lies in the definition of "regularly". My original intention was indeed "regularly visited on screen, perhaps more than 3 times in 3 separate episodic arcs", but it seems that there is practically no location that fits this (with the exception of like...Earth or Vulcan and the like). As such, I have accepted the answer that has stations visited more than once.