It wasn't long ago that River Oaks was considered the richest ZIP code in the nation. But time can take its toll, and even $15 million mansions need a facelift sometimes. During the last three decades, Houston's Exterior Worlds has helped with that. The company specializes in "high-end landscape design," repairing and building outdoor fountains, luxury swimming pools and even outdoor kitchens. That's along with the normal range of services. Exterior Worlds helps keep River Oaks one area that non-Houstonians can envy.