Cavern in Pictured Rocks National Lakeshore on Lake Superior, Michigan (© Kenneth Keifer/Getty Images)

A lava flow hits water as a tour boat passes, Hawaii Volcanoes National Park (© Patrick Kelley/Getty Images)

Isola Bella, Lake Maggiore, Piedmont, Italy (© Massimo Ripani/eStock Photo)

Lightning storm in the Tortolita Mountain foothills, north of Tucson, Arizona, in the Sonoran Desert (© Jack Dykinga/Minden Pictures)

White-tailed doe and fawn in Wisconsin (© Karel Bock/Shutterstock)

Oyster farm offshore from Notojima Island, Ishikawa prefecture, Japan (© divedog/Shutterstock)

Former lifeguard station on the island of Rügen, Mecklenburg-Western Pomerania, Germany (© DR pics/Shutterstock)

Young humpback whale giving its mother a hug off the coast of the Tongan archipelago (© Biosphoto/Alamy)

Infinity Bridge in Stockton-on-Tees, England (© Robert Smith/Alamy)

Lassen Peak in Lassen Volcanic National Park, California (© Engel Ching/Shutterstock)

Lion cubs hiding in tall grass in the Kalahari Desert region of Botswana (© Jami Tarris/Getty Images)

Bioluminescent sea fireflies along the shore of Okayama, Japan (© tdub_video/Getty Images)

Fossil skeleton of a Tyrannosaurus rex (© Corbin17/Alamy)

Matera, Italy (© Marco Ilari/Getty Images)

A view of Monument Valley Navajo Tribal Park from Hunts Mesa, Navajo Nation, between Arizona and Utah (© AWL Images/Danita Delimont)

Caves and coastal features at low tide on the Bay of Fundy, near St. Martins, New Brunswick, Canada (© Jamie Roach/Shutterstock)

An adult burrowing owl emerges from its burrow at sunset in Davis, California (© Neil Losin/Tandem Stills + Motion)

Borobudur in central Java, Indonesia (© Oleh Slobodeniuk/Getty Images)

Tennessee Woman Suffrage Monument in Centennial Park, Nashville, Tennessee (© jejim120/Alamy)

A group of curious emperor penguins in Antarctica (© Mint Images Limited/Alamy)

The Highlands of Iceland (© Kevin Krautgartner/Offset by Shutterstock)

Multicolored lobster buoys, Acadia National Park, Maine (© Cheri Alguire/Shutterstock)

Urquhart Castle and Loch Ness in the Scottish Highlands (© AWL Images/Danita Delimont)

Stars reflected in the Totensee, a mountain lake at Grimsel Pass, Switzerland (© magodevita/Getty Images)

Caño Cristales river in the Serranía de la Macarena region of Colombia (© Jorge Iván Vásquez Cuartas/Getty Images)

The Tasman Sea from Punakaiki on South Island, New Zealand (© Maurizio Rellini/Sime/eStock Photo)

Spotted Lake in the Okanagan region of British Columbia, Canada (© Galyna Andrushko/Shutterstock)

Sailing stone at Racetrack Playa in Death Valley National Park, California (© Patrick Walsh/Getty Images)

Château d'If in Marseille, France (© Boris Stroujko/Shutterstock)

Bicycle sculptures at the Col d'Aubisque, Hautes Pyrenees, France (© Fco. Javier Sobrino/age fotostock)

Hay bales in a field in Jutland, Denmark (© Nick Brundle Photography/Getty Images)