1. In 1782, on June 20th, the Great Seal of the United States was officially adopted by Congress. The seal is used to authenticate and legalize government documents.

2. In 1837, the first regular issue of "The Sun," a daily newspaper, was published in New York City. It would go on to become one of the most significant newspapers in the country.

3. On June 20, 1877, the first street railway in Brooklyn opened. The railway ran from Fulton Ferry to Greenwood Cemetery and was a significant development in public transportation.

4. In 1936, the Triborough Bridge was opened to the public. The bridge connects the boroughs of Manhattan, Queens, and the Bronx and was one of the largest public works projects of its time.

5. In 2014, on June 20th, the "City of Water Day" event was held in New York City. The event celebrates the importance of waterways for transportation, commerce, and recreation in the city.