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Photograph by Sam Abell
Ergs are vast expanses of sand dunes like this area in Oman. Sometimes they are also called sand seas because the dunes look and act like very slowly moving ocean waves. -
Photograph by Stephen Alvarez
Strong winds created this sand dune in Oman. About 10 percent of deserts are covered by sand dunes. -
Photograph by Medford Taylor
These ripples of sand are formed by the constant winds in Australia's Simpson Desert. It rains less than 7.8 inches (200 millimeters) per year there. -
Photograph by Carsten Peter
Palm trees surround a lake in Takartibah, Libya. A green place like this in the middle of a desert is called an oasis. -
Photograph by Ed George
A cactus stands guard over a lonely desert in Baja, Mexico. Deserts are found on every continent. Deserts receive less than 10 inches (25 centimeters) of rain (or snow) a year.
