Druids have gathered on a London hilltop to celebrate the autumn equinox, which marks the end of summer.

Coming midway between the summer and winter solstices, the equinox - derived from the Latin aequinoctium, from aequus (equal) and nox (night) - is a time when the hours of day and night are equal, as the Sun is directly over the Equator. 

Gathering on London's Primrose Hill, dozens of druids, clad in long white robes and chanting mystical hymns, made their way up to the summit to mark the autumn equinox, as they have been doing for hundreds of years.

Druidry follows the flow of the seasons, marking the changes at sites across the UK. It has roots in pagan religions predating Christianity, which are thought to have been a part of Celtic and Gaulish culture in Iron Age Europe. An 18th-century revival in such practices has continued to this day, in many different forms; some followers identify as pagan, others as Christian.

But it's not just druids who celebrate the autumn equinox.

It's also marked in China as the Chinese Farmers' Harvest Festival, which was established in 2018 by China's State Council to celebrate the harvest for farmers across the country, which has a rich agricultural history.

Farmers celebrate the festival with activities ranging from skill contests and products exhibitions to parties and carnivals. The tradition of celebrating harvest is especially well preserved in many regions inhabited by ethnic groups in China.

Here's how  the harvest festival has evolved in China:

https://news.cgtn.com/news/2019-09-23/The-evolution-of-China-s-harvest-festival-KdWX4eOvtK/index.html
 

As part of the Druids' ceremony participants place fruit on the ground, to give thanks for the summer season which has just passed and raise hopes for the harvest to come.

"There are a lot of druids in the world and for us it is a science of life, it is not really a religion," said Stephanie Dennis, one of those taking part in the ceremony. "It is about learning to be the best people we could be. It includes learning, and sharing the light of the sun. This is why the sun is very important in our ceremonies like longest day, longest night and midpoint. So we all try to be a balance ourselves."

"It is all about the balance, and this time of year is the harvest," explained Dennis. "That is the balance between planting the seed and eating the product. This is in the harvest. We are here trying to remember what our harvest is and to be grateful for it."

"Druids today are a range of different groups," said Ronald Hutton, Professor of History at the University of Bristol, "united by the concept of the ancient druid as a priest or priestess of the natural world, with a mystical sense of union with the land itself and with the ancient peoples who shaped it."