Although the Tunnel is open during business hours on Monday through Friday, The Shops at Houston Center are open Saturdays from 10:00 a.m.-3:00 p.m. The city s portion of the Tunnel linking the Theater District Parking Garage to Bayou Place and performance halls remains open 24/7. For more information about the Theater District Parking Garage, call 713/228-0003.Discover Houston Tours offers guided TunnelWalk Rail Tours for individuals and groups on weekdays. Check the Calendar for scheduled tours or call 713/222-9255 to book a private tour for your group of 10 or more.http://www.discoverhoustontours.com/Welc��
It is actually a tunnel system. Over six miles of them. Mostly restaurants.It can be accessed from the street level of many buildings.
The underground is mostly food but there is some shopping but I am not sure. Its so spread out. The underground covers blocks
I have been there recently but when I went it was basically food stores and small stores. nothing special