The boost in altitude was broadening the view to include much of Houston. Several miles east of Allen’s Landing, the bayou spilled into a vast bay extending far to the south, where it was sealed off from the Gulf of Mexico by a barrier island. Much of that waterfront was dominated by industrial complexes and shipping facilities on a scale that would be impressive if you had never seen Rotterdam. Directly south was the downtown high-rise district, lodged in the center of a spiderweb of freeways. Any one of those freeways, traced outward, supported its own chain of sub-metropolises. "I’m not gonna insult y’all’s intelligence by explaining compound interest," T.R. said. "The value of the real estate in greater Houston today is one point seven five trillion dollars. Big number. But it’s just six percent annual interest compounded for two hundred years from that starting point. Now just stash that number in your short-term memory for a spell while we go look at some other unique exhibits."