Houston lands in this spot because of a lack of municipal revenue and reduced funds spent on structures, sewers, utilities and solid waste management. The city of about 2.2 million was previously No. 2. On the bright side: You might not want to find the skeletons of dead rats under the house, but the fossil remains of dinosaurs and other creatures can be explored at the Houston Museum of Natural Science. In addition, the museum offers a realistic display of many creatures native to Texas, including alligators, river otters and mountain lions.