1. Winter Solstice: December 21 marks the winter solstice, which is the shortest day and longest night of the year. New Mexico is known for its stunning sunsets and sunrises, which are even more brilliant during this time of year.

2. Pueblo Revolt: In 1680, the Pueblo people of New Mexico launched a successful revolt against Spanish colonial rule. The rebellion was led by the charismatic Tewa leader Popé, who coordinated a surprise attack on multiple Spanish towns throughout the region, which changed the course of history for the state.

3. Statehood: On December 21, 1912, New Mexico became the 47th state to join the Union. This historic event marked the end of a long struggle for statehood, which included years of debate and negotiation with the federal government.

4. Los Alamos National Laboratory: December 21, 1942, marked the official formation of the Los Alamos National Laboratory, which was established as part of the Manhattan Project to develop the first atomic bomb during World War II. Today, the laboratory remains an important center for nuclear research and technology.

5. White Sands Missile Range: The White Sands Missile Range in southern New Mexico was established on December 21, 1945. The range is still used today for missile testing and other military operations, and has played an important role in both national defense and space exploration over the years.