Kids cool off in the spray of water from an outdoor waterpark fountain in downtown San Diego, California, U.S. July 5, 2018. REUTERS/Mike Blake

Supporters of U.S. Republican presidential candidate Ted Cruz listen as he speaks at King's Pointe Resort in Storm Lake, Iowa January 6, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Ted Cruz speaks at King's Pointe Waterpark and Resort in Storm Lake, Iowa January 6, 2016. REUTERS/Mark Kauzlarich

A couple sits on a bench as people swim in a pool on a hot summer day in the western Austrian village of Ellmau, August 12, 2015. REUTERS/Dominic Ebenbichler

Children slide down a water slide on a hot summer day in the western Austrian village of Ellmau, August 12, 2015. REUTERS/Dominic Ebenbichler

Children slide down a water slide on a hot summer day in the western Austrian village of Ellmau, August 12, 2015. REUTERS/Dominic Ebenbichler

People swim in a pool on a hot summer day in the western Austrian village of Ellmau, August 12, 2015. REUTERS/Dominic Ebenbichler

Children slide down a water slide on a hot summer day in the western Austrian village of Ellmau, August 12, 2015. REUTERS/Dominic Ebenbichler

A person slides down a huge water pipe at a park on a hot summer day in Brussels, Belgium, August 7, 2015. REUTERS/Francois Lenoir

People slide down a huge water pipe at a park on a hot summer day in Brussels, Belgium, August 7, 2015. REUTERS/Francois Lenoir

A person slides down a huge water pipe at a park on a hot summer day in Brussels, Belgium, August 7, 2015. REUTERS/Francois Lenoir

A visitor is silhouetted as she slides down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. Temperatures in Austria's capital Vienna rose up to 37 degrees Celsius (98 Fahrenheit), but Austria's Central Institute for Meteorology and Geodynamics predicts a possible record temerature of 38 degrees Celsius (100 Fahrenheit) in the next days. REUTERS/Leonhard Foeger

Visitors are silhouetted as they slide down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. Temperatures in Austria's capital Vienna rose up to 37 degrees Celsius (98 Fahrenheit), but Austria's Central Institute for Meteorology and Geodynamics predicts a possible record temerature of 38 degrees Celsius (100 Fahrenheit) in the next days. REUTERS/Leonhard Foeger

A visitor is silhouetted as she slides down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. Temperatures in Austria's capital Vienna rose up to 37 degrees Celsius (98 Fahrenheit), but Austria's Central Institute for Meteorology and Geodynamics predicts a possible record temerature of 38 degrees Celsius (100 Fahrenheit) in the next days. REUTERS/Leonhard Foeger

A visitor is silhouetted as she slides down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. Temperatures in Austria's capital Vienna rose up to 37 degrees Celsius (98 Fahrenheit), but Austria's Central Institute for Meteorology and Geodynamics predicts a possible record temerature of 38 degrees Celsius (100 Fahrenheit) in the next days. REUTERS/Leonhard Foeger

Visitors are silhouetted as they slide down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. Temperatures in Austria's capital Vienna rose up to 37 degrees Celsius (98 Fahrenheit), but Austria's Central Institute for Meteorology and Geodynamics predicts a possible record temerature of 38 degrees Celsius (100 Fahrenheit) in the next days. REUTERS/Leonhard Foeger

A visitor is silhouetted as she slides down a huge water pipe at a public swimming pool on a hot sunny day in Vienna, Austria, July 22, 2015. Temperatures in Austria's capital Vienna rose up to 37 degrees Celsius (98 Fahrenheit), but Austria's Central Institute for Meteorology and Geodynamics predicts a possible record temerature of 38 degrees Celsius (100 Fahrenheit) in the next days. REUTERS/Leonhard Foeger

Wikie (L), a killer whale, swims with her calf in Marineland aquatic park in Antibes, southeastern France, December 12, 2013. Wikie, gave birth three weeks ago to a calf which now weighs 150kg (330 pounds). REUTERS/Eric Gaillard (FRANCE - Tags: SOCIETY ANIMALS)

Youths slide down a huge water slide at a public swimming pool in Kabul October 4, 2013. Inside a non-descript building in central Kabul, residents of the battle-hardened capital have a new and unusual form of escape - a state-of-the-art water park. In addition to towering slides, there is a huge wave pool, a restaurant, whirlpool, sauna and lavish play area for young children, including girls who are allowed to mix with the opposite sex until the age of about 10. Picture taken on October 4. To match story AFGHANISTAN-WATERPARK/ REUTERS/Omar Sobhani (AFGHANISTAN - Tags: SOCIETY SPORT SWIMMING)

A child plays at a water park during the Eid al-Fitr holiday in Serpong district, on the outskirts of Jakarta August 13, 2013. REUTERS/Beawiharta (INDONESIA - Tags: SOCIETY RELIGION TPX IMAGES OF THE DAY)

A child plays on a bungee trampoline at a water park during the Eid al-Fitr holiday in Serpong district, on the outskirts of Jakarta August 13, 2013. REUTERS/Beawiharta (INDONESIA - Tags: SOCIETY RELIGION)

A girl enjoys speeding down a water chute at Kongressbad public swimming bath in Vienna August 8, 2013. Temperatures were expected to rise up to 39 degrees Celsius (102 Fahrenheit) on Thursday, national weather service agency ZAMG reported. REUTERS/Heinz-Peter Bader (AUSTRIA - Tags: SOCIETY ENVIRONMENT)

An elderly man speeds down a water chute at Kongressbad public swimming bath in Vienna August 8, 2013. Temperatures were expected to rise up to 39 degrees Celsius (102 Fahrenheit) on Thursday, national weather service agency ZAMG reported. REUTERS/Heinz-Peter Bader (AUSTRIASOCIETY ENVIRONMENT - Tags: SOCIETY ENVIRONMENT TPX IMAGES OF THE DAY)

A man rides a water chute at an Aqua arena in Mogyorod, near Budapest, as temperatures reached 38 degrees Celsius (100 degrees Fahrenheit) in Hungary, August 6, 2013. REUTERS/Laszlo Balogh (HUNGARY - Tags: ENVIRONMENT)

A woman rides in a water chute at an Aqua arena in Mogyorod, near Budapest, as temperatures reached 38 degrees Celsius (100 degrees Fahrenheit) in Hungary, August 6, 2013. REUTERS/Laszlo Balogh (HUNGARY - Tags: ENVIRONMENT)

A boy slides down a water chute in a public swimming pool in Thun August 1, 2013. REUTERS/Ruben Sprich (SWITZERLAND - Tags: ENVIRONMENT SOCIETY TPX IMAGES OF THE DAY)

Dolphins jump near a man dressed as Santa Claus at the Marineland aquatic park in Antibes December 11, 2012. REUTERS/Eric Gaillard (FRANCE - Tags: ANIMALS SOCIETY)

People enjoy a water slide at Copa Copana water park at Haidari suburb near Athens July 11, 2012. Temperatures in many cities throughout the country reached 40 degrees Celsius (104 degrees Fahrenheit) and is expected to stay at these levels for the next few days, according to the weather forecast service. REUTERS/Yorgos Karahalis (GREECE - Tags: ENVIRONMENT SOCIETY)

People enjoy water slides as others line up to take their turn at Copa Copana water park at Haidari suburb near Athens July 11, 2012. Temperatures in many cities throughout the country reached 40 degrees Celsius (104 degrees Fahrenheit) and is expected to stay at these levels for the next few days, according to the weather forecast service. REUTERS/Yorgos Karahalis (GREECE - Tags: ENVIRONMENT SOCIETY)

People ride a water chute in an Aqua arena in Mogyorod near Budapest July 9, 2011. Temperatures reached 36 degrees Celsius (96.8 degrees Fahrenheit) during the weekend in Hungary. REUTERS/Laszlo Balogh (HUNGARY - Tags: SOCIETY ENVIRONMENT)

A boy enjoys a water chute in an Aqua arena in Mogyorod near Budapest July 9, 2011. Temperatures reached 36 degrees Celsius (96.8 degrees Fahrenheit) during the weekend in Hungary. REUTERS/Laszlo Balogh (HUNGARY - Tags: SOCIETY ENVIRONMENT IMAGES OF THE DAY)

A woman slides down a big water slide at a water park in Lima March 20, 2011, ahead of World Water Day on Tuesday. REUTERS/Enrique Castro-Mendivil (PERU - Tags: SOCIETY)

Boys try to cool off in a Waco, Texas water park as temperatures topped 100
degrees, August 7, 2003. Authorities have issued heat warnings for Central
and North Texas as temperatures are expected to stay above 100 degrees for
the next several days. NO RIGHTS CLEARANCES OR PERMISSIONS ARE REQUIRED FOR THIS IMAGE REUTERS/Jeff Mitchell

JM/HB

Eleven-year-old Wilson Ridgewater cools off in a Waco, Texas, water park as
temperatures topped 100 degrees, August 7, 2003. Authorities have issued
heat warnings for Central and North Texas as temperatures are expected to
stay above 100 degrees for the next several days. NO RIGHTS CLEARANCES OR PERMISSIONS ARE REQUIRED FOR THIS IMAGE REUTERS/Jeff
Mitchell

JM/HB

Eleven-year-old Wilson Ridgewater cools off in a Waco, Texas, water park as
temperatures topped 100 degrees, August 7, 2003. Authorities have issued
heat warnings for Central and North Texas as temperatures are expected to
stay above 100 degrees for the next several days. Pictures of the month
August 2003 NO RIGHTS CLEARANCES OR PERMISSIONS ARE REQUIRED FOR THIS IMAGE REUTERS/Jeff Mitchell

JM/HB