Niagara Falls is the collective name for three waterfalls that straddle the international border between Canada and the United States, more specifically, between the province of Ontario and the state of New York. They form the southern end of the Niagara Gorge.

From largest to smallest, the three waterfalls are the Horseshoe Falls, the American Falls and the Bridal Veil Falls. The Horseshoe Falls lie mostly on the Canadian side and the American Falls entirely on the American side, separated by Goat Island. The smaller Bridal Veil Falls are also located on the American side, separated from the other waterfalls by Luna Island. The international boundary line was originally drawn through Horseshoe Falls in 1819, but the boundary has long been in dispute due to natural erosion and construction

The Niagara Falls are renowned for their beauty and as a valuable source of hydroelectric power. Managing the balance between recreational, commercial, and industrial uses has been a challenge for the stewards of the falls since the 19th century.

Monument Valley is a region of the Colorado Plateau characterized by a cluster of vast sandstone buttes, the largest reaching 1,000 ft (300 m) above the valley floor. It is located on the Arizona-Utah state line, near the Four Corners area. The valley lies within the range of the Navajo Nation Reservation and is accessible from U.S. Highway 163.

Monument Valley is officially a large area that includes much of the area surrounding Monument Valley Navajo Tribal Park, a Navajo Nation equivalent to a national park.

Visitors may pay an access fee and drive through the park on a 17-mile (27 km) dirt road (a 2-3 hour trip). Parts of Monument Valley are accessible only by guided tour, such as Mystery Valley and Hunts Mesa.

Yosemite National Park is a United States National Park spanning eastern portions of Tuolumne,Mariposa and Madera counties in the central eastern portion of the U.S. state of California

Over 3.7 million people visit Yosemite each year: most spend their time in the seven square miles (18 km2) of Yosemite Valley

Yosemite is internationally recognized for its spectacular granite cliffs, waterfalls clear streams, Giant Sequoia groves, and biological diversity. Almost 95% of the park is designated wilderness.

Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park

supports a diversity of plants and animals.