1. The Hawaiian monarchy abolished kapu system: On March 30, 1819, King Kamehameha II and his wife, Queen Kamamalu, abolished the kapu system in Hawaii. Kapu was a set of rules that governed every aspect of Hawaiian life, including social structure, behavior, and religion. Its abolition was a significant step towards the modernization of Hawaiian society.

2. Hawaii officially became a US territory: On March 30, 1900, President William McKinley signed the Organic Act, officially making Hawaii a US territory. This followed years of political upheaval and a US-backed overthrow of the Hawaiian monarchy in 1893.

3. A tsunami struck Hilo: On March 30, 1946, a magnitude 8.1 earthquake in the Aleutian Islands triggered a tsunami that devastated the town of Hilo on the Big Island of Hawaii. The tsunami killed 159 people and caused extensive damage to buildings and infrastructure.

4. Hawaii Five-O premiered: On March 30, 1968, the television series Hawaii Five-O premiered on CBS. The show, which followed the adventures of a fictional Honolulu police department, became a cultural icon and played a significant role in promoting Hawaii as a tourist destination.

5. Hawaii recognized same-sex civil unions: On March 30, 2011, Governor Neil Abercrombie signed a bill recognizing same-sex civil unions in Hawaii. The law was a significant step towards marriage equality in the state and paved the way for Hawaii to become one of the first US states to legalize same-sex marriage.