The summer solstice is the longest day of the year in the Northern Hemisphere, so soak up some of those direct sunbeams (safely, of course) and celebrate the start of summer with these 15 facts.

1. In 2023, the summer solstice falls on June 21.

The summer solstice always occurs between June 20 and June 22, but because the calendar doesn't exactly reflect the Earth’s rotation, the precise time shifts slightly each year. In 2023, the sun will reach its greatest height in the sky for the Northern Hemisphere on Wednesday, June 21, at 10:57 a.m. EDT.

2. On the summer solstice, the sun will be directly overhead at the Tropic of Cancer.

While the entire Northern Hemisphere will see its longest day of the year on the summer solstice, the sun is only directly overhead at the Tropic of Cancer (23 degrees 27 minutes north latitude).

3. The name comes from the fact that the sun appears to stand still.

The term solstice is derived from the Latin words sol (sun) and sistere (to stand still), because the sun's relative position in the sky at noon does not appear to change much during the solstice and its surrounding days. The rest of the year, the Earth’s tilt on its axis—roughly 23.5 degrees—causes the sun's path in the sky to rise and fall from one day to the next.

4. One of the world’s biggest bonfires was part of a summer solstice celebration.

Cultures around the world have held celebrations in conjunction with the solstice for hundreds of years. Among these is Midsummer, which is celebrated on June 24 in Scandinavia and other northern European countries. In 2016, the people of Ålesund, Norway, set a world record for the tallest bonfire with their 155.5-foot celebratory blaze (their record was broken in 2019 by Austrian Carnival festivities).

5. The hot weather follows the sun by a few weeks.

You may wonder why, if the solstice is the longest day of the year—and thus gets the most sunlight—the temperature usually doesn’t reach its annual peak until a month or two later. It’s because water, which makes up most of the Earth’s surface, has a high specific heat, meaning it takes a while to both heat up and cool down. Because of this, the Earth’s temperature takes about six weeks to catch up to the sun.

6. Thousands of people gather at Stonehenge to celebrate the summer solstice.

People have long believed Stonehenge was the site of ancient druid solstice celebrations because of the way the sun lines up with the stones on the winter and summer solstices. While there’s no proven connection between Celtic solstice celebrations and the megalithic monument, these days, thousands of modern pagans gather at the landmark to watch the sunrise.

7. Pagans celebrate the summer solstice with symbols of fire and water.

In Paganism and Wicca, Midsummer is celebrated with a festival known as Litha. In ancient Europe, the festival involved rolling giant wheels lit on fire into bodies of water to symbolize the balance between fire and water.

8. In Ancient Egypt, the summer solstice heralded the new year.

In Ancient Egypt, the summer solstice preceded the appearance of the Sirius star, which the Egyptians believed was responsible for the annual flooding of the Nile that they relied upon for agriculture. Because of this, the Egyptian calendar was set so that the start of the year coincided with the appearance of Sirius, just after the solstice.

9. The ancient Chinese honored the yin on the summer solstice.

In ancient China, the summer solstice was the yin to the winter solstice’s yang—literally. Throughout the year, the Chinese believed, the powers of yin and yang waxed and waned in reverse proportion to each other. At the summer solstice, the influence of yang was at its height, but the celebration centered on the impending switch to yin. At the winter solstice, the opposite switch was honored.

10. In Alaska, the summer solstice is celebrated with a midnight baseball game.

Each year on the summer solstice, the Alaska Goldpanners of Fairbanks celebrate their status as the most northerly baseball team on the planet with a game that starts at 10 p.m. and stretches well into the following morning—without the need for artificial light—known as the Midnight Sun Game. The tradition originated in 1906 and was taken over by the Goldpanners in 1960, the first year of their existence.

11. The Earth is actually at its farthest from the sun during the solstice.

You might think that because the solstice occurs in summer, it means the Earth is closest to the sun in its elliptical revolution. However, the Earth is actually closest to the sun around the time the Northern Hemisphere experiences winter and is farthest away near the summer solstice. The warmth of summer comes exclusively from the tilt of the Earth’s axis, and not from how close it is to the sun at any given time.

12. The summer solstice marks a dark time in science history.

Legend has it that it was on the summer solstice in 1633 that Galileo Galilei was forced to recant his declaration that the Earth revolves around the sun; even with doing so, he still spent the rest of his life under house arrest.

13. An alternative calendar had an extra month named after the solstice.

In 1902, a British railway system employee named Moses B. Cotsworth attempted to institute a new calendar system that would standardize the months into even four-week segments. To do so, he needed to add an extra month to the year. The additional month was inserted between June and July and named Sol because the summer solstice would always fall during this time. Despite Cotsworth’s traveling campaign to promote his new calendar, it failed to catch on.

14. In Ancient Greece, the solstice festival marked a time of social equality.

The Greek festival of Kronia, which honored Cronus, the god of agriculture, often coincided with the solstice. The festival was distinguished from other annual feasts and celebrations in that enslaved people and freemen participated in the festivities as equals.

15. Ancient Rome honored the goddess Vesta on the solstice.

In Rome, midsummer coincided with the festival of Vestalia, which honored Vesta, the Roman goddess who guarded virginity and was considered the patron of the domestic sphere. On the first day of this festival, married women were allowed to enter the temple of the Vestal virgins, from which they were barred the rest of the year.

A version of this story originally ran in 2018; it has been updated for 2023.

This article was originally published on www.mentalfloss.com as 15 Facts About the Summer Solstice.