Snake Alley in Burlington, Iowa

Built in 1894 and completed in 1898, Snake Alley in Burlington, Iowa was originally devised by three German immigrants who wanted a faster link between Heritage Hill and Burlington's downtown business district. Because of the steep grade, the road was made to wind down the hill with bricks laid at an angle so horses had better footing as they descended. San Francisco's iconic Lombard Street has a few more turns in it, but Ripley's Believe It, Or Not! once recognized Snake Alley as the 'Crookedest Street in the World'.
 

Mississippi River

Old Fort Madison in Iowa

The original Fort Madison was in use between 1808 to 1813, and was built by the U.S. military to patrol the Upper Mississippi in what is present day Iowa. The fort didn't have a long life, but was one of three posts constructed by the army to gain control over the newly acquired territories following the Louisiana Purchase in 1803.

Fort Madison was abandoned and set ablaze during the summer of 1813. As the frontier became a battleground during the War of 1812, attacking tribes allied with the British had forced the army to withdraw. Today, a re-creation of the old fort can be found in Fort Madison, Iowa.
  

Mississippi River in Fort Madison, Iowa.