1. May 17, 1856: The town of Clear Lake, Iowa was founded. The town is located in north-central Iowa and is a popular tourist destination for its namesake lake, which offers boating, fishing, and other recreational activities.

2. May 17, 1948: The first locomotive on the Iowa Traction Railway was delivered. The railway, which was originally constructed in 1896, is a short-line electric railroad that runs between Mason City and Clear Lake.

3. May 17, 1968: The novel "The Bridges of Madison County" by Robert James Waller was published. The novel, which tells the story of a love affair between a National Geographic photographer and a married woman in Madison County, Iowa, went on to become a best-seller and was later adapted into a film starring Clint Eastwood and Meryl Streep.

4. May 17, 1995: The Iowa State Capitol was designated a National Historic Landmark. The building, which was completed in 1886, is located in Des Moines and serves as the seat of government for the State of Iowa.

5. May 17, 2009: The Iowa Supreme Court issued a unanimous ruling legalizing same-sex marriage in the state. Iowa became the third state in the United States to allow same-sex marriage, following Massachusetts and Connecticut.