Today Google celebrates the solstice, which marks the end of spring and the start of summer in the Southern Hemisphere. It also marks the first day of winter on the astronomical calendar in the Northern Hemisphere.
Thursday was the shortest day of the year in the Northern Hemisphere, and the longest day of the year for those south the Equator.
Sunlight hours ranged from as little as zero in some northern parts of Alaska to over 14 hours in parts of Australia and South Africa.
Below we explain both phenomena.
Shortest day. Officially the first day of winter in the astronomical calendar, the winter solstice is the day with the shortest period of daylight and longest night of the year.
The Northern Hemisphere is pointed at its furthest distance from the sun, bringing less light and colder temperatures.
Thursday 21, 16:28 GMT. Winter and summer solstice happens at the same time for everyone, and this year it took place on Thursday, December 21, at 16:28 GMT.
The winter solstice is significant in the Northern Hemisphere because days will get progressively longer and lighter as we approach the longest day of the year on June 21.
The longest day of the year. However below the Equator, countries got to experience the summer solstice as the seasons flipped.
During the summer solstice, the sun travelled its longest path across the sky, giving people who live in the southern hemisphere more than 12 hours of daylight.
This makes December, January and February the peak of summer in countries such as Australia and South Africa.
Ancient rituals. Ancient cultures and rituals around the world mark the summer and winter solstice. For many, this is the beginning of the return of the sun, darkness turning into light, birth and rebirth.
Peruvians stage mock Incan sacrifices to celebrate the Sun Festival.
In China, people celebrate with rice ball dumplings to celebrate Dongzhi (Winter Arrives).
Iranians wait up for the sun to rise, marking the end of evil during the festival of Shab-e Yalda (Night of Birth)