"Most Americans have no idea about Houston," he said. "We're not the city that is part of the image that so many people have of cow town and rodeos. The city is happy to have the world come to Houston and see what we've done."
Super Bowl comes as Houston recovering from latest oil bust →
"He's indefatigable, just incredible," said Stephen Klineberg, co-director of the Institute for Urban Research at Houston's Rice University.
Texas Democrat campaigns far and wide →