Questions About Conmvention Center

What is this place in houston, and does it have a specific name?

When I was in Houston for a robotics competition sometime at the beginning of the year, some friends and i noticed some multicolored buildings outside on a huge field, when we went inside to see, it was a HUGE underground car park, there was a big multicolored building outside, im pretty sure it was the conmvention center. Anybody know what im talking about? Just to specify, I know the name of the center now, but i'm wondering mainly about the underground car park now.