1. Rhode Island was the first colony to declare independence from British rule on May 15, 1776. This event is regarded as a milestone in American history, as it paved the way for other colonies to declare their own independence and ultimately led to the formation of the United States of America.

2. On May 15, 1914, the first American factory to manufacture rayon was opened in Pawtucket, Rhode Island. This synthetic fiber was a revolutionary product at the time, and its development marked a significant step forward in the textile industry.

3. May 15, 1930 saw the birth of one of Rhode Island's most famous natives, baseball player Bill "Spaceman" Lee. Lee played for the Boston Red Sox and Montreal Expos during his career and was known for his eccentric personality and signature high leg kick while pitching.

4. On May 15, 1932, the Rhode Island State House was officially dedicated. This iconic building is the home of Rhode Island's government and is notable for its impressive dome, which is the fourth largest self-supporting marble dome in the world.

5. In more recent years, May 15 has become an important date for Rhode Island's LGBTQ+ community. On May 15, 2013, the state became the tenth in the US to legalize same-sex marriage. This landmark decision was celebrated by many and paved the way for further progress in LGBTQ+ rights in both Rhode Island and across the country.