The June 21 summer solstice, which has been celebrated for thousands of years as a symbolic of renewal, fertility and harvest, will coincide with a full moon for the first time since 1948.

The summer solstice, which comes in late June each year, in the northern hemisphere comes from the Latin word “solstitium,” meaning “sun stands still.” It is the time of the year when the sun reaches its maximum elevation overhead at 23 degrees 27 minutes north latitude. (The shortest day of the year is the Winter Solstice in December, when the sun’s elevation is the lowest — and vice versa south of the equator.)

The summer solstice has numerous links to ancient cultures that have celebrated it as a symbolic time of renewal, fertility and harvest. Prehistoric Stonehenge in England was built to align with both the summer and winter solstices. The monument is so precise that the rising sun only reaches the middle of the stones one day in June each year when it shines on the central alter.

Over 20,000 people are expected to converge at Stonehenge on Tuesday to celebrate the once-in-a-lifetime “Strawberry Moon,” described by some as the UK’s effort to match America’s “Burning Man.”

Seasons happen in the United States due to the 23.5 degree tilt of the earth’s axis to the sun. As the earth rotates on its axis like a gyroscope, the North Pole continuously points at a fixed point in space near the North Star. Half the year, the southern hemisphere is more exposed to the sun than is the northern hemisphere. The other half, the northern hemisphere is more exposed to the sun than the southern hemisphere.

The Slooh Astronomy Network (SAN) will celebrate the solstice with a free webcast of the stars at 5 p.m. PST on Tuesday. SAN has partnered with a series of powerful observatories across the globe,  from the Canary Islands, Chile, Hawaii, Middle East, Africa and Australia. This year’s program will feature astronomer Bob Berman and host Paul Cox talking about the moon. Virtual attendees will be able to control StarShare cameras to take live pictures through the world’s top telescopes.

“Having a full moon land smack on the solstice is a truly rare event,” Berman said in a statement. “We probably won’t push people off pyramids like the Mayans did, but Slooh will very much celebrate this extraordinary day of light with fascinating factoids and amazing live telescope feeds.”