1. On January 22, 1952, a devastating fire swept through the historic Chesapeake and Ohio Canal National Historical Park in Maryland, destroying many of the canal buildings and artifacts. The fire prompted a major restoration effort, which led to the establishment of the park as a national historical site in 1961.

2. On January 22, 1971, the U.S. Supreme Court ruled in Tinker v. Des Moines Independent Community School District that students have a constitutional right to free speech in schools, unless their speech "materially and substantially disrupts" the school's educational mission. The case was brought by Mary Beth Tinker, a high school student from Iowa who was suspended for wearing a black armband to school in protest of the Vietnam War.

3. On January 22, 1982, Air Florida Flight 90 crashed into the Potomac River shortly after takeoff from Washington National Airport, killing 78 people on board and four people on the ground. The crash was caused by a combination of pilot error, mechanical failure, and severe weather conditions. The tragedy prompted new safety regulations for commercial aviation.

4. On January 22, 2008, the Maryland General Assembly overrode Governor Martin O'Malley's veto of a bill that would require Wal-Mart and other large employers to spend at least 8% of their payroll on healthcare benefits or pay into a state fund to provide healthcare for the uninsured. The law, which became known as the "Wal-Mart bill," was the first of its kind in the United States.

5. On January 22, 2013, Maryland became the eighth state to legalize same-sex marriage, after Governor O'Malley signed a bill passed by the General Assembly. The law went into effect on January 1, 2013, but opponents collected enough signatures to put the issue on the ballot as a referendum, which passed with 52% of the vote. Maryland became the first state to legalize same-sex marriage through popular vote.