 Every city has its iconic piece of infrastructure. Paris has the Eiffel Tower, San Francisco the Golden Gate Bridge, and Houston, well, Houston has the muddy brown waters of the Houston Ship Channel. You'd be hard-pressed to find visiting the Houston Ship Channel on anybody's bucket list, yet this 110-year-old dredging masterpiece is critical to U.S. oil and gas exports. And without it, it was built soon after the discovery of oil in the area, by the way. Houston just would not be Houston.