1) On April 7, 1913, the state of Delaware ratified the 17th Amendment to the U.S. Constitution, which established the direct election of senators by the people of each state. This amendment shifted the political power from state legislatures to the people and was a significant step towards enlarging democratic participation in the United States.

2) On April 7, 1942, one of the most destructive oil refinery fires in the history of Delaware occurred at the Atlantic Refining Company plant. The fire was caused by a pipeline rupture and ignited a massive explosion, killing 6 workers and injuring dozens more. The blast was so powerful that it shattered windows as far as 9 miles away and caused $3 million worth of damages.

3) On April 7, 1967, Delaware Governor Charles L. Terry, Jr. signed legislation that allowed for the creation of the University of Delaware's College of Marine Studies, which later became the current College of Earth, Ocean, and Environment. The college has gained international recognition for its research in marine and environmental sciences, and its graduates have gone on to assume prominent roles in academia, government, and industry.

4) On April 7, 1994, the DuPont Company announced its acquisition of Conoco, a major oil and gas company, for $8.2 billion. The deal was one of the largest mergers in corporate history and significantly expanded DuPont's presence in the energy sector.

5) On April 7, 2015, Delaware Governor Jack Markell signed a bill that made the state the 20th in the U.S. to legalize same-sex marriage. The law granted same-sex couples the same legal rights and protections as opposite-sex couples, including the right to marry and adopt children. The signing of the bill marked a significant victory for the LGBTQ+ community and supporters of marriage equality in Delaware.