Houston, Texas has a unique way to avoid the elements and traffic. Six miles long and twenty feet below the streets of Downtown Houston is an Underground tunnel system covering 95 city blocks. The Downtown Tunnel System is an interconnected series of restaurants, and shops, normally open on weekdays, from 6:00 a.m. to 6:30 p.m. Each system has a name that can be excessed from the street or from inside an office building. There is the Tunnel Loop, W. Walker tunnel, Louisiana Tunnel, Harris County Tunnel, Lamar Tunnel, and Rusk Tunnel.
In addition to the tunnels, there are three Skywalks at McKinney, Louisiana, and Dallas.
check here for availability, excess, and events to the Downtown underground.