A instructor (2nd L) from the Philippine Mermaid Swimming Academy assists participants of a monofin swimming summer workshop as they practise floating in the water of a private pool in Paranaque city, metro Manila April 5, 2014. The Philippine Mermaid Swimming Academy workshops, which were originally conducted on the beaches of Boracay Island, central Philippines, currently cost 1,800 pesos per person ($40) for a two-hour session. (Photo by Romeo Ranoco/Reuters)

A combination picture shows Will Adam, 14, snowboarding down a street on Beacon Hill during a large winter blizzard in Boston, Massachusetts, United States January 27, 2015 (top), and a woman looking at her phone as she walks down the same street June 13, 2015. Outdoor scenes in Boston show local residents enjoying balmy weather amid lush greenery as the summer solstice approaches on 21 June. The very same locations suffered heavy snowstorms last winter, with snow ploughs, skiers and snowboarders battling the drifts. Boston got 275.8 cm of snow over the winter, the most since 1872, when records began. A few months after the snowstorms, Brian Snyder revisited the same places and shot pictures at exactly the same locations. (Photo by Brian Snyder/Reuters)

A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

Two children jumping through a water hydrant's shower on a New York street. They have come from a neighbouring co-educational playgroup organised by the city's Police Department. (Photo by Orlando/Getty Images). 1950

Cordwood construction is a method of natural building that originated roughly one thousand years ago in Greece and Siberia. This method involves using pieces of wood that slightly protrude from the mortar, giving the walls an attractive appearance. Usually, the walls are made 12 to 24 inches thick. However, in some parts of Canada, the walls can be as thick as 36 inches. This method appeals to many people due to its ease of construction economy of resources. Cordwood Construction can be separated into two main types: mortar-insulation-mortar (M-I-M) and Throughwall. M-I-M is a more preferable and widely used choice as it allows for better insulating properties.

A woman leans against one of the stones of the Stonehenge monument on the summer solstice near Amesbury, Britain on June 21, 2017. The annual festival attracts hundreds of people to the 5000 year old stone circle to mark the longest day in the northern hemisphere. sunrise was at 4.52am and was celebrated by dancing, music, and ritualistic events around the stones. (Photo by Neil Hall/Reuters)

“In the late afternoon after a rain, genji botaru fireflies (luciola cruciate) dance above the swollen creek. The rocks darkened by the rain reflecting the blue sky, and the yellow-green ribbon of the glow from the fireflies, make a beautiful contrast”. – Takehito Miyatake. (Photo by Takehito Miyatake/Steven Kasher Gallery)

Last weekend, the National Building Museum in Washington, D.C., opened a 10,000 square-foot ball pit to the general public, and everyone cheered that, finally, someone made their childhood dreams come true.