A Belgian shrimp fisherman rides a carthorse to haul a net out in the sea to catch shrimps during low tide at the coastal town of Oostduinkerke, Belgium July 3, 2015. At the end of each fishing session, the fishermen and their mounts leave the water to empty the net's contents into two wicker baskets fixed on each side of the horse. This traditional method of catching shrimps along the North Sea coast, which dates back to some 500 years, attracts tourists every summer. In 2013, Unesco recognized shrimp fishing on horseback as an intangible cultural heritage. (Photo by Yves Herman/Reuters)

Participants arrive at the finish line during the annual Maldon Mud Race in Maldon, east England on May 7, 2017. Originating in 1973, the race involves competitors racing around a course through the River Blackwater in Essex at low tide. (Photo by Daniel Leal-Olivas/AFP Photo)

A man watches a wave hit a rock pool at Curl Curl beach as large swell hits the East Coast of Australia on June 6, 2016 in Sydney, Australia. Torrential rain over the weekend saw streets and homes flooded while wind gusts up to 120km per hour brought down trees and powerlines. A king tide has also seen beachside homes evacuated on Sydney's northern beaches as large waves erode the coast. (Photo by Cameron Spencer/Getty Images)

Tourists pose with pigeons in the flooded St. Mark's Square in Venice, on November 7, 2014. The high water, a combination of high tides and a strong Scirocco wind in the Adriatic Sea, stood at 110 centimeters early on November 7. The city has for years been wrestling with the problems posed by the threat of rising sea levels. (Photo by Olivier Morin/AFP Photo)

Split Apple Rock is a geological rock formation in The Tasman Bay off the northern coast of the South Island of New Zealand. Made of granite, it is in the shape of an apple which has been cut in half. It is a popular tourist attraction in the waters of the Tasman Sea approximately 50 metres off the coast between Kaiteriteri and Marahau. The rock sits in shallow water at low tide and is accessible by wading. It is also a point of interest for the many tourist boats and pleasure craft which operate along the shores of the Abel Tasman National Park. The cleft to produce two sides of the 'apple' was a natural occurrence. It is unknown when this happened and therefore the cleaving of the rock has attracted mythological explanations.

A neighborhood watch volunteer stands guard on her street on February 9, 2017 in Peronia, Guatemala. Residents of Peronia, south of Guatemala City organized block by block to secure their community after ten of their neighbors in January were killed, they say, for refusing to pay extortion money to gangs. Armed with machetes and sticks, residents take turns each night, baring strangers' entry into their neighborhoods. Violence and poverty continue to drive emigration from Central America to the United States, even as the Trump administration moves to tighten border security. (Photo by John Moore/Getty Images)

Owner Nicole Graham works with volunteers from CFA and SES tries to dig out her horse “Astro” who became stuck up to his neck in mud at Avalon Beach on February 26, 2012 in Geelong, Australia. The tide was fast-rising, but the rescuers managed to get him out in time. (Photo by Peter Ristevski/Newspix)

A Puffin returns to it's nest with a beak full of sand eels on June 25, 2011 on Inner Farne, England. The Farne Islands, which are run by the National Trust, are situated two to three miles off the Northumberland coastline. The archipeligo of 16-28 separate islands (depending on the tide) make the summer home to approximately 100,000 pairs of breeding seabirds including around 36,000 Puffins, 32,000 Guillemots and 2,000 pairs of Arctic Terns. The species of birds which nest in internationally important numbers include Shag, Sandwich Tern and Arctic Tern. The coastline around The Farnes are also the breeding ground to one of Europe's largest Grey Seal colonies with around 4,000 adults giving birth to 1500 pups every year. (Photo by Dan Kitwood/Getty Images)