John Muir recognized how difficult it is to change our personal perspectives of the world around us. He believed that mankind is just one part of an interconnected natural world and championed its protection. In 1903 Muir guided President Theodore Roosevelt on a historic camping trip to Yosemite. Muir shared his concerns of environmental degradation, calling for the expansion of the National Park System. Throughout his presidency, Roosevelt protected five national parks, 18 national monuments, 55 national bird sanctuaries and wildlife refuges, and 150 national forests.