 The group may have been the first non-indigenous people to see Yosemite Valley.The Walker Party probably visited either the Tuolumne or Merced Groves of giant sequoia, becoming the first non-indigenous people to see the giant trees, but journals relating to the Walker party were destroyed in 1839, in a print shop fire in Philadelphia.In the winter of 1844, Lt. John C. Frémont, accompanied by Kit Carson, was the first American to see Lake Tahoe.