The longest day of the year in the Northern Hemisphere. At the solstice, Earth's axial tilt reaches its maximum lean toward the Sun, placing the Sun at its highest point in the sky and giving us the most daylight we'll see all year. After today, the days start getting shorter, slowly at first, then faster through late summer.

Cultures across history have marked this moment, from Stonehenge alignments to midsummer festivals.

It's also a useful anchor: solstices and equinoxes define the astronomical seasons, making this the official first day of summer.

Happy summer, Northern hemisphere folks, and enjoy the daylight!