Upper and second sections of Gullfoss Falls on the Hvita River; the river carries water from a glacier 25 miles away and ultimately flows intto the Atlantic Ocean, Iceland

Upper section of Gullfoss Falls on the Hvita River; the river carries water from a glacier 25 miles away and ultimately flows to the Atlantic Ocean, Iceland

Upper and second sections of Gullfoss Falls on the Hvita River; the river carries water from a glacier 25 miles away and ultimately flows intto the Atlantic Ocean, Iceland

Kerid, a volcanic crater lake 6,500 years old (fairly recent in geologic terms); formed when cone of volcano collapsed on itself down to water table, Iceland

Kerid, a volcanic crater lake 6,500 years old (fairly recent in geologic terms); iformed when cone of the volcano collapsed on itself down to water table, Iceland

River Varma, near Hveragerdi, Iceland

Dynjandis River breaching mountain pass to create waterfalls in Westfjords, Iceland. Visible are all five steps or falls below the initial and largest falls, as well as the fjord (in the foreground) into which the water flows.

Dynjandis River breaching mountain pass to create waterfalls in Westfjords, Iceland. Visible are three of the five steps or falls below the initial and largest falls.

Dynjandis River breaching mountain pass to create waterfalls in Westfjords, Iceland. Visible are four of the five steps or falls below the initial and largest falls, and the water flowing towards the fjord.

One of the five steps or falls below the Dynjandis waterfall, the initial and largest of the falls where the Dynjandis River flows through a mountain pass in Westfjords, Iceland.

One of the five steps or falls below the Dynjandis waterfall, the initial and largest of the six falls after the Dynjandis River flows through a mountain pass in Westfjords, Iceland.

Álftafjörður, Iceland Dynjandis River emptying into the fjord in Westfjords, Iceland after a series of six waterfalls. The lines in the sides of the mountain are the terraces or layers resulting from the geological processes that formed the mountain; glaciers carved the sides of the mountain making the lines visible

Dettifoss waterfalls, one of most powerful in Europe, on Jokusla River, Iceland

Selffoss waterfalls on Jokulsa River, Iceland

Rock formations, remains of volcanic craters that have been eroded by the Jokulsa a Fjollum glacial river, Iceland

Botnstjorn pond in Asbyrgi Canyon, which was formed by extraordinary glacial flooding of the Jokulsa a Fjollum River around 10,000 and 3,000 years ago, Iceland

View of eroded walls of Asbyrgi Canyon, which was formed by extraordinary glacial flooding of the Jokulsa a Fjollum River around 10,000 and 3,000 years ago, Iceland

Nykurhylsfoss waterfall is first one in Fossardalur valley ("valley of the waterfalls") and is associated with folklore creatures, Iceland

Mulafoss waterfall in Mulagljufur Canyon in the "valley of the waterfalls", Fossardalur Valley, fed by the largest glacier in Iceland

Fossa River in Valley of the Waterfalls (Fossardalur), Iceland

Crossing the Fossa River in "super vehicles" (50" plus tires, elevated frames, upgraded motors and suspensions, snorkels for air for engines when underwater, etc.) in the Valley of the Waterfalls (Fossardalur), Iceland

Rio Maranon, a main tributary of the Amazon River, Upper Amazon, Peru

Full moon over a tributary of the Amazon River, Upper Amazon, Peru (taken from a skiff)

Full moon over expedition ship (20 guests) on a tributary of the Amazon River, Upper Amazon, Peru, (taken from a skiff)

Paddling hand-carved, wooden twin-hulled dugouts through a rain forest in the Amazon Natural Park, Upper Amazon, Peru

Remote tributary of the Amazon River in a rain forest, Upper Amazon, Peru

Mara River, Tanzania (from a hot air balloon)

Bridalveil Falls during golden hour, Yosemite National Park, California

Lake Magadi in Ngorongoro Crater, Tanzania (taken from top of the crater's rim)

Yosemite Creek, Yosemite National Park, California

Wetlands in Ngorongoro Crater with morning clouds draping the crater's rim, Tanzania

Yosemite Creek, Yosemite National Park, California

Lake Magadi, with wildebeest along its shoreline, in Ngorongoro Crater, Tanzania

Yosemite Falls, Yosemite National Park, California

Bridalveil Falls and the Merced River in the morning glow, Yosemite National Park, California

Upper Yosemite Fall, first of three sections, and the one with the largest drop (1,430 feet), of Yosemite Falls, Yosemite National Park, California; on the top of ridge to left of the Fall is a hiking trail that goes to the top of the Fall

View from Cook's Meadow, on the floor of Yosemite Valley, of Upper Yosemite Fall, Yosemite National Park, California

Mirror Lake, a wide part of a creek that offers great reflections of Half Dome in the spring and early summer due to snowmelt, but becomes a grteen meadow in Fall-Winter as the creek dries up,Yosemite National Park, California

Rapids of Merced River beside lodge near an entrance to Yosemite National Park, California

Rapids of Merced River flow under a pedestrain bridge on trail to Vernal Falls, Yosemite National Park, California

Two forks of Merced River join downstram from Vernal Falls, Yosemite National Park, California

Section of Merced RIver in valley below Vernal Falls with SierraNevada peaks in background, Yosemite National Park, California

Stream flowing from Vernal Falls, Yosemite National Park, California

Rakia Gorge and River (water is blue from glacial melt) on Canterbury Plains, South Island, New Zealand

Rugged terrain near Tasman Glacier, New Zealand, accessed via 8WD all terrain vehicle

Lake Wakatipu at sunset, Queenstown, New Zealand

Lady Bowen Falls flowing into Milford Sound, New Zealand