1. 1872: The first electrically powered streetcar made its debut in San Francisco, California. The streetcar was an important transportation innovation that helped shape the city's mobility system.

2. 1937: The groundbreaking ceremony for the Golden Gate Bridge took place in San Francisco. The bridge was completed in 1938 and has become an iconic symbol of San Francisco and California.

3. 1959: Fidel Castro arrived in San Francisco, marking the start of his United States tour. The visit was significant as it represented a pivotal moment in US-Cuban relations, at a time when Castro was gaining power in Cuba.

4. 1985: The San Francisco Symphony debuted the world premiere of John Adams' "Harmonielehre". The composition was well received and helped cement Adams' reputation as one of the most important living American composers.

5. 2005: The California Supreme Court issues a landmark ruling that provided same-sex couples with the legal right to marry. The ruling marked a significant moment in the fight for LGBTQ+ rights, and California became the second state in the United States to legalize same-sex marriage.