1. The first official news of the discovery of the Comstock Lode was published on May 15, 1859. The Comstock Lode was one of the richest silver and gold mines in history and played a significant role in Nevada's early economic growth.

2. The city of Reno was officially incorporated as a municipality on May 15, 1903. It became the largest city in Nevada outside of Las Vegas and played a significant role in the growth of the state's tourism industry.

3. The Hoover Dam was dedicated on May 15, 1935. The dam was a massive engineering feat that provided water and hydroelectric power to much of the Southwest, including Las Vegas and Los Angeles.

4. On May 15, 1956, the first atomic bomb test took place at the Nevada Test Site, located in Nye County, Nevada. This was the first of more than 1,000 nuclear explosion tests that took place at the site over the following decades.

5. The first legal same-sex marriages in Nevada took place on May 15, 2015, following the ruling of a federal judge that struck down a ban on gay marriage in the state. Nevada was one of the first states in the nation to grant same-sex couples the right to marry.