Conservation workers have embarked on a new round of work at the famous Stonehenge site in southern England. Repairs are expected to last for two weeks, according to reports in the Guardian and Smithsonian Magazine.

The stones have cracked and fallen over several times in modern history, according to one report. And, at the turn of the 20th century, a strong winter storm caused one of the monument’s horizontal lintels to crash to the ground.

The last time there were major renovations to the monument was in the 1950s and ’60s, when fierce winds knocked over a historic boulder, according to a 2018 blog post by English Heritage, the charitable trust that oversees Stonehenge.

“But these 20th-century patch-ups no longer hold up to today’s standards,” according to the Smithsonian. Wind and water have lashed the stones over thousands of years, causing cracks and other structural problems.

Conservator James Preston uses a pointing spoon atop scaffold erected inside the stone circle at Stonehenge as specialist contractors from SSH Conservation repair defects from previous repairs, carried out the 1950’s. Picture date: Tuesday September 14, 2021. Photo by Ben Birchall/PA Images via Getty Images.

Heather Sebire, English Heritage’s senior curator for Stonehenge, said that conservators are focusing their attention on Stone 122, a horizontal piece that fell and cracked in 1900. (Sebire did not immediately respond to a request for comment.)

Conservators patched Stone 122 back together in 1958, but more recent examination revealed that the concrete mortar was cracking.

“It was a bit of a mess up there, to be honest,” Sebire told the Guardian.

A scaffold is erected inside the stone circle as specialist contractors from SSH Conservation repair defects from previous repairs, carried out the 1950’s, on a trilithon in the stone circle and carry out vital conservation work at Stonehenge, Wiltshire. September 14, 2021. Photo by Ben Birchall/PA Images via Getty Images.

Recent laser scans have also shown deep natural holes in some of Stonehenge’s boulders. Meanwhile, extreme temperatures related to climate change have further strained these holes and could pose more stability issues in the future, Sebire said.