Nepal mountaineer Lhakpa Sherpa broke her own world record for most summits of Mount Everest. (Prakash Mathema/AFP via Getty Images)

Two women made Mount Everest history Thursday, as one became the youngest U.S. woman to summit and the other broke her own world record for most summits of the peak by a woman.

Lhakpa Sherpa reached the summit of the world’s highest peak for the 10th time on Thursday – marking the most times that any woman has climbed Everest. She broke her own record as the most successful female climber of Everest.

Also on the mountain was Lucy Westlake, a native of Naperville, Illinois. At 18 years, 6 months and 8 days, Westlake became the youngest U.S. woman – by a month – to reach the summit of Mount Everest. She surpasses the record held by Samantha Larson, who set the record in 2007 and has held it for 15 years.

Westlake began the trek on April 18 and reached the summit 25 days later.

“I came into the climb well-acclimated as I had spent the past five weeks training with some of the best distance runners in the world in the highlands of Kenya at 7,000 feet,” Westlake said in a news release. “I am a distance runner as well, so my fitness level helped to endure the long, difficult days on the mountain. I also have a lot of experience climbing so the challenges of Everest felt familiar.”

Westlake, at the age of 12 in 2016, became the youngest girl to climb the highest points of all 50 U.S. states with a summit of Denali in Alaska – the highest peak in North America – with her father, Rodney.

After her completion of Everest, Westlake could go on to become the youngest woman to complete the Explorers Grand Slam. The feat includes summiting the highest peaks on each continent and skiing the last degree to the North and South poles. Westlake has already summited Kilimanjaro (Africa), Elbrus (Europe), Denali (North America), Aconcagua (South America) and Everest (Asia).

She needs to reach the two poles and climb mountains on two continents – Carstensz Pyramid in Papua New Guinea, Oceania, and Mount Vinson in Antarctica – which she intends to complete in 2023.