1. On April 20, 1775, the town of Machias, Maine witnessed the first naval battle of the American Revolution. Several armed vessels of the British Royal Navy attempted to capture the town's supply of lumber and ship masts, but were overpowered by a group of local militia and ship captains. This victory helped inspire the patriots and establish naval dominance in the region.

2. April 20, 1820 marked the official separation of Maine from Massachusetts and the establishment of the 23rd state in the Union. The process had been years in the making, with numerous debates and negotiations between the two entities, but ultimately Maine gained its own identity and sense of autonomy.

3. One of Maine's most famous individuals, author and poet Edna St. Vincent Millay, was born on April 20, 1892 in Rockland. Millay went on to win the Pulitzer Prize in poetry in 1923 and became known for her feminist ideals and experimental writing styles.

4. On April 20, 1914, the city of Bangor experienced what has been dubbed the "Great Bangor-Fire of 1914." A devastating blaze broke out in a downtown clothing store and quickly spread, engulfing numerous other businesses and buildings. The fire burned for almost 30 hours, destroyed 55 acres, and left over 1000 people homeless.

5. In more recent history, on April 20, 2013, the Canadian singer and songwriter Justin Bieber performed a sold-out concert at the Cumberland County Civic Center in Portland, Maine. The show was part of his "Believe" tour and drew thousands of screaming fans of all ages, many of whom camped out for days beforehand to secure their spot.