Havasu Falls, Arizona

Havasu Falls drops 90 to 100 feet (27 to 30 m) over a travertine cliff into a series of plunge pools on Havasu Creek, a tributary of the Colorado River deep inside Havasu Canyon, a side canyon of the Grand Canyon. The creek's striking blue-green colour comes from a high concentration of dissolved calcium carbonate, the same mineral that slowly builds the pale travertine ledges and dams visible around the pools. The falls and the surrounding canyon sit entirely within the Havasupai Indian Reservation, land the Havasupai Tribe has called home for centuries.

The name Havasupai means "people of the blue-green water," a direct reference to this creek. There's no road to the falls: visitors reach them by hiking roughly 10 miles from the Hualapai Hilltop trailhead down into the canyon — 8 miles to the village of Supai, then another 2 miles to the falls and campground — or by mule train or helicopter. A permit reserved in advance through the Havasupai Tribe is required to camp or visit.

Flash floods have reshaped Havasu Falls many times over the past century; before a major flood in 1910 it flowed as a single unbroken sheet known as Bridal Veil Falls, and the notch at its lip has shifted repeatedly since, sometimes splitting the flow into multiple strands as in this photograph. As a jigsaw, the scene breaks into natural sections: the pale sky and canyon rim at the top form an easy start, the layered red rock face and falling water make a detailed centrepiece, and the turquoise pool and sandy bank in the foreground give a calm, forgiving finish.