The 1938 American Karakoram expedition to K2, more properly called the First American Karakoram expedition, investigated several routes for reaching the summit of K2, an unclimbed mountain at the second highest mountain in the world. Charlie Houston was the leader of what was a small and happily united climbing party. After deciding the Abruzzi Ridge was most favorable, they made good progress up to the head of the ridge at on July 19, 1938. However, by then their supply lines were very extended, they were short of food and the monsoon seemed imminent. It was decided that Houston and Paul Petzoldt would make a last push to get as close to the summit as they could and then rejoin the rest of the party in descent. On July 21 the pair reached about . In favorable weather they were able to identify a suitable site for a higher camp and a clear route to the summit.