Desert bighorn sheep in Valley of Fire State Park, Nevada (© Rachid Dahnoun/Cavan Images)

Aerial view of Khao Sok National Park, Surat Thani, Thailand (© Peetatham Kongkapech/Getty Images)

Jackson Square, New Orleans, Louisiana (© SeanPavonePhoto/Getty Images)

Southern yellow-billed hornbills in Kruger National Park, South Africa (© Richard Du Toit/Minden Pictures)

Eucalyptus trees, Megalong Valley, Blue Mountains National Park, NSW, Australia (© Andrew Peacock/TANDEM Stills + Motion)

Dr. Anna Howard Shaw leading a suffrage parade in 1910s New York City (© Bettmann/Getty Images)

Paro Taktsang, a Buddhist monastery in Bhutan (© Baron Reznik/Getty Images)

Polar bear cub, Churchill, Manitoba, Canada (© Eric Baccega/NPL/Minden Pictures)

Castle Stalker on Loch Laich, Argyll, Scotland (© WLDavies/Getty Images)

Sandstone hoodoos, Bryce Canyon National Park, Utah (© Stephen Matera/TANDEM Stills + Motion)