Synchronous fireflies, Great Smoky Mountains National Park, Tennessee (© Floris Van Bruegel/Minden Pictures)

Aerial image of the Great Barrier Reef, Australia (© AirPano LLC/Amazing Aerial Agency)

Gemsbok (Oryx gazella) in sand dunes, Namibia (© Sergey Gorshkov/Minden)

South Kaibab Trail in Grand Canyon National Park, Arizona (© Roman Khomlyak/Getty Images)

Black sand beach at Wai'ānapanapa State Park, Maui, Hawaii (© Matt Anderson Photography/Getty Images)

'Priscilla the Parrotfish' art installation at Como Park Zoo & Conservatory, St. Paul, Minnesota (© Michael Siluk/UCG/Universal Images Group via Getty Images)

The chalk cliffs of Étretat, Normandy, France (© MarcelloLand/Getty Images)

Pueblo Bonito, Chaco Culture National Historical Park, New Mexico (© Ian Shive/Tandem Stills + Motion)

Humpback whale (© Philip Thurston/Getty Images)

Hot air balloons in Cappadocia, Türkiye (© Anton Petrus/Getty Images)

Porto Cathedral, Portugal (© Reinhard Schmid/Huber/eStock Photo)

Goliath heron, Kruger National Park, South Africa (© Johan Swanepoel/Alamy)

Prickly pear cactus, Big Bend National Park, Texas (© Tim Fitzharris/Minden Pictures)

Trees with Spanish moss over a boardwalk in the Okefenokee Swamp, Folkston, Georgia (© Emmer Photo/Alamy)

US Capitol building and US flags, Washington, DC (© Orhan Cam/Shutterstock)

Hawksbill sea turtle swimming near Akajima, Okinawa, Japan (© Robert Mallon/Getty Images)

'Paddle Out for Unity' event in San Diego, California (© Brandon Colbert Photography/Getty Images)

Common tern father with chick, Nickerson Beach, Long Island, New York (© Vicki Jauron, Babylon and Beyond Photography/Getty Images)

City Hall lit up for Juneteenth in San Francisco, California (© yhelfman/Shutterstock)

Bald eagle, Tongass National Forest, Alaska (© Jaynes Gallery/Shutterstock)

Stonehenge, Salisbury Plain, Wiltshire, England (© Captain Skyhigh/Getty Images)

Amazon rainforest, Peru (© Rhett Ayers Butler/Getty Images)

Monarch butterflies feeding from wildflowers (© bookguy/Getty Images)

Nha Phu Bay, Nha Trang, Vietnam (© Thang Tat Nguyen/Getty Images)

Al-Khazneh (the Treasury), Petra, Jordan (© WitthayaP/Shutterstock)

Château de Villandry and its garden, Loire Valley, France (© VLADJ55/Shutterstock)

Sedona, Arizona (© Jonathan Ross/Getty Images)

Rainbow flags and confetti, Reykjavík, Iceland (© Arctic-Images/Getty Images)

Banyak Islands, Sumatra, Indonesia (© fbxx/Getty Images)

Brown bear mother and cub, Lake Clark National Park and Preserve, Alaska (© Carlos Carreno/Getty Images)