June 21 marks this year's summer solstice in the Northern Hemisphere, the day with the longest period of daylight and the shortest night of the year. Across cultures, the occasion is celebrated with a variety of customs and festivities.

In China, the day marks the arrival of Xiazhi, the tenth of the country's 24 solar terms. Chinese people traditionally eat noodles on the summer solstice to celebrate the wheat harvest. Other traditions include honoring ancestors, admiring blooming lotus flowers and seeking relief from the summer heat.

In many other parts of the world, people celebrate Midsummer on or around the date of the summer solstice with bonfires, music and gatherings.

In Nordic countries such as Sweden and Finland, people raise maypoles, sing and dance, gather with family and friends, and enjoy seasonal foods. In the United Kingdom, thousands gather at Stonehenge each year to witness the summer-solstice sunrise, as the ancient monument is aligned with the rising sun on the day.

Although traditions vary from place to place, they all reflect people's connection to nature and their celebration of the longest day of the year.