Bear cubs playing by a lake (© Sergey Ivanov/Getty)

View of Paris, France, with the Eiffel Tower taken from Notre Dame Cathedral (© Funny Solution Studio/Shutterstock)

New York City’s Empire State Building is seen lit up before Earth Hour in 2011 (© Eric Thayer/Reuters)

Auroville, India (© Vikram Ramakrishnan/Shutterstock)

A rufous-tailed hummingbird in Costa Rica (© Juan Carlos Vindas/Getty Images)

Sap-collecting buckets in Brome-Missisquoi, Quebec, Canada (© Roderick Chen/SuperStock)

Cherry blossoms over the Meguro River, Tokyo, Japan (© taketan/Getty Images)

Athens, Greece, for Greek Independence Day (© junnyphoto/Getty Images)

Sea otters in Prince William Sound, Alaska, 30 years after the Exxon Valdez oil spill (© Patrick Endres/plainpicture)

From NASA’s Terra satellite, an image of fallstreak holes in clouds over the southern United States (© NASA)

Water wheel in the Tashkurgan Grassland, Tashkurgan Tajik Autonomous County, Xinjiang, China (© Ratnakorn Piyasirisorost/Getty Images)

A baobab grove near Bandia Wildlife Reserve in Senegal (© Frans Lanting/plainpicture)

Galah (Eolophus roseicapilla) flock flying in Western Australia (© Yva Momatiuk and John Eastcott/Minden Pictures)

Fireworks at the Plaza del Ayuntamiento for las Fallas festival in Valencia, Spain (© Helena G.H/Shutterstock)

Shoreline near Tofino on Vancouver Island, British Columbia, Canada (© Robert Postma/plainpicture)

Department of the Taoiseach lit up for the St Patrick's Festival in Dublin, Ireland (© David Soanes Photography/Getty Images)

Fingal Head with a rock fisherman on the headland (© Auscape/UIG via Getty Images)

At the Arch of Septimius Severus in the Roman Forum for the ides of March (© Pietro Canali/eStock Photo)

Circular agricultural fields in Morgan County, Colorado (© Jim Wark/Getty Images)

A view of Uranus taken from spacecraft Voyager 2 in 1986 (© NASA)

Channels of the Rio Tinto in Spain (© Oscar Diez Martinez/Minden Pictures)

Canberra’s National Carillon at dawn (© Peter Ptschelinzew/Lonely Planet Images/Getty Images)

Royal Highland Fusiliers playing the bagpipes on top of the Sydney Opera House (© James D Morgan/Shutterstock)

Grapes on the vine in Mendoza, Argentina, for the National Grape Harvest Festival (© javarman3/iStock/Getty Images Plus)

Policewomen from the United Nations Stabilization Mission in Haiti attend a ceremony to mark International Women's Day in 2016 (© Hector Retamal/AFP/Getty Images)

Wildflowers in bloom at Lost Dutchman State Park in Arizona (© Tim Fitzharris/Minden Pictures)

Cefalù on Mediterranean Sea in Sicily, Italy (© Tuul & Bruno Morandi/eStock Photo)

Members of the Wild Red Flame Mardi Gras Indians in New Orleans, Louisiana (© Chris Graythen/Getty Images)

Leopard snoozing in a tree in Namibia (© M. Watsonantheo/SuperStock)