A man driving a vintage car reacts as he passes by crabs crossing a highway on their way to spawn in the sea in Playa Giron, Cuba on April 25, 2017. Each year, after the first spring rains, millions of red, yellow and black landcrabs march for days from the surrounding forests to the bay on Cuba's southern coast to spawn in the sea. (Photo by Alexandre Meneghini/Reuters)

A local resident stumbles as he wades through flood water on a residential street in Carlisle, Britain December 6, 2015. British police have declared a major incident in northern England after prolonged heavy rain caused widespread flooding and forced emergency services to evacuate residents from their homes. (Photo by Phil Noble/Reuters)

When he's driving, New York-based painter Gregory Thielker takes in the views that change from moment to moment: the road, the sky, other cars. “Inside the car it's easy to forget the outside temperature, humidity, the noise of the road”, he says. “But something happens when rain interrupts the view: the lens through which we are seeing is revealed. Water both obscures and highlights the landscape”. Gregory Thielker's exhibition “Between here and now” will be at Castor Gallery in lower Manhattan from early March. Here: “Complete Stop”. (Painting by Gregory Thielker)

Two men help each other cross a street covered in deep mud in Copiapo, Chile, Thursday, March 26, 2015. Unusually heavy thunder storms and torrential rains that began on Tuesday have blocked roads, caused power outages and affected some 600 people on this normally dry region. (Photo by Aton Chile/Marcelo Hernandez/AP Photo)

A massive positive cloud-to-ground lightning strike hits in Coolidge, Arizona, 31 August 2016. Thousands of rain drops merge to form mammoth travelling sheets of water in these breathtaking monsoons. Veteran storm chaser and photographer Mike Olbinski captured the stunning beauty of monsoons in timelapses and stills while chasing storm systems across America. (Photo by Mike Olbinski/Barcroft Images)

People splash mud water in a paddy field on National Paddy Day in Tokha village, on the outskirt of capital Kathmandu, Nepal, 29 June 2021. Nepal is celebrating National Paddy Day with various events on 29 June. On this day, known as Asar Pandra, farmers begin the annual rice planting season and mark the day with various festivities such as preparing rice meals with muddy water, mud being a symbol for a prosperous season. Sixty percent of Nepal's agriculture industry relies on monsoon rain while 40 percent is carried out through irrigation. Agriculture is a major contributor to the country's GDP. (Photo by Narendra Shrestha/EPA/EFE)

Tim Laman is a field biologist and wildlife photojournalist. His pioneering research in the rain forest canopy in Borneo led to a PhD from Harvard and his first National Geographic article in 1997. Since then, he has pursued his passion for exploring wild places and documenting little-known and endangered wildlife by becoming a regular contributor to National Geographic. He has eighteen articles to his credit to date, all of which have had a conservation message. Some have focused on endangered species such as Orangutans or Hornbills, while others, such as a series of articles on Conservation International’s Biodiversity Hotspots, have highlighted regions under intense pressure.

A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.