Photographers from around the world are submitting images to National Geographic for the 2017 Nature Photographer of the Year contest. Their shots fall into one of four categories: wildlife, landscapes, underwater and aerials. Here is a sample:

1. “Ice Cave”

Imagem de uma pessoa de pé do lado de fora da abertura de uma caverna de gelo (© Sergey Pesterev/concurso “Fotógrafo de Natureza do Ano” de 2017 da National Geographic)
This is one of many ice caves on Olkhon Island, Lake Baikal, in eastern Siberia, Russia. (© Sergey Pesterev/2017 National Geographic Nature Photographer of the Year)

2. “Swimming over the sleepers”

Mergulhadores nadando sobre cachalotes (© Franco Banfi/concurso “Fotógrafo de Natureza do Ano” de 2017 da National Geographic)
Divers swim over a pod of sleeping sperm whale in a shot taken in the Caribbean Sea near Dominica. Sperm whales dive as deep as 1,000 meters in search of squid to eat. (© Franco Banfi/2017 National Geographic Nature Photographer of the Year)

3. “Nature’s fury”

Grande tornado no céu sobre área rural (© Colt Forney/concurso “Fotógrafo de Natureza do Ano” de 2017 da National Geographic)
A rotating supercell thunderstorm dances across Kansas farmland. (© Colt Forney/2017 National Geographic Nature Photographer of the Year)

4. “Weaver and nest”

Pássaro amarelo inserindo grama em ninho pendurado (© Federico Rizzato/concurso “Fotógrafo de Natureza do Ano” de 2017 da National Geographic)
An African weaver, known for its nest-building techniques, in action. The photographer waited hours to capture the moment. (© Federico Rizzato/2017 National Geographic Nature Photographer of the Year)

5. “Swimming with salmon”

Vista aérea do homem nadando em direção a um cardume de peixes dispersos (© Brandon Cole/concurso “Fotógrafo de Natureza do Ano” de 2017 da National Geographic)
A man in an Alaskan lake swims through a pool of spawning salmon. (© Brandon Cole/2017 National Geographic Nature Photographer of the Year)

6. “Porcelain crab”

Crab poking claws through underwater vegetation (© Marek Koszorek/2017 National Geographic Nature Photographer of the Year)
A porcelain crab peeks out through an anemone as it feeds on drifting plankton. (© Marek Koszorek/2017 National Geographic Nature Photographer of the Year)

7. “Great gray owl”

Gray owl flying near ground (© Harry Collins/2017 National Geographic Nature Photographer of the Year)
A great gray owl on the hunt for rodents in a field in New Hampshire, in the northeastern United States. (© Harry Collins/2017 National Geographic Nature Photographer of the Year)

8. “Courage”

Lion crouched and facing pack of hyenas (© Adam Zaff/2017 National Geographic Nature Photographer of the Year)
A lioness faces off against a pack of hyenas in Kenya. After a 30-minute standoff, the lioness got away unscathed. (© Adam Zaff/2017 National Geographic Nature Photographer of the Year)

9. “Flamingos and their nests”

Flamingos dashing over water away from nests (© Ge Xiao/2017 National Geographic Nature Photographer of the Year)
Flamingos leave their eggs in nests on Tanzania’s Lake Natron, a breeding ground for many flamingos. (© Ge Xiao/2017 National Geographic Nature Photographer of the Year)

10. “The duel”

Two zebras fightding (© Sonalini Khetrapal/2017 National Geographic Nature Photographer of the Year)
Two zebras scuffle near a waterhole in Namibia’s Etosha National Park. (© Sonalini Khetrapal/2017 National Geographic Nature Photographer of the Year)

11. “Rock pool”

Aerial view of pool surrounded by waves and rocks (© Todd Kennedy/2017 National Geographic Nature Photographer of the Year)
Oblivious to waves crashing about, a swimmer moves through a rock pool near Sydney, Australia, at high tide. (© Todd Kennedy/2017 National Geographic Nature Photographer of the Year)

12. “Sneeze!”

Iguana sneezing spray of water near two red crabs (© M. Engelmann/2017 National Geographic Nature Photographer of the Year)
Galápagos marine iguanas sneeze to expel excess salt water after they feed in the ocean. (© M. Engelmann/2017 National Geographic Nature Photographer of the Year)

13. “Sword”

Close-up view of hummingbird in flight (© Sanjeev Bhor/2017 National Geographic Nature Photographer of the Year)
A sword-billed hummingbird, in flight in Ecuador. The bird’s rapid movements make it difficult to capture a focused image. (© Sanjeev Bhor/2017 National Geographic Nature Photographer of the Year)

14. “Drift”

Man of war jellyfish floating in water at night (© Matthew Smith/2017 National Geographic Nature Photographer of the Year)
A Pacific man of war navigates close to the beach on a summer morning breeze. Thousands of them wash up on Australia’s east coast every year. (© Matthew Smith/2017 National Geographic Nature Photographer of the Year)

15. “Volcano”

Volcano erupting at night (© Vladimir Voychuk/2017 National Geographic Nature Photographer of the Year)
A view of the erupting Klyuchevskaya Sopka volcano in Russia’s Kamchatka Peninsula. (© Vladimir Voychuk/2017 National Geographic Nature Photographer of the Year)

One first-place winner will be chosen from each of the four categories, and the winning photographs will be published on National Geographic’s website. The grand-prize winner will be chosen from among the category winners and will be announced in December.