American artists have drawn criticism after making stunning, intricate sculptures by pouring hot liquid aluminium into anthills.

A laborer works at an upside-down house under construction at Fengjing Ancient Town, Jinshan District, south of Shanghai, March 17, 2014. Workers are putting the final touches on this eccentric tourist attraction built at the “China Folk Painting Village”. Furniture will also be placed upside down in the house, which is expected to open the public in April, according to local media. (Photo by Carlos Barria/Reuters)

Tourists from Holland peak through a crack in a still-existing portion of the Berlin Wall at the main memorial to the Wall in Bernauer Strasse on the 22nd anniversary of the fall of the Wall on November 9, 2011 in Berlin, Germany. The Berlin Wall, erected by the communist authorities of then East Germany in 1961, divided the city and prevented East Germans from travelling west until the collapse of the Eastern Bloc in 1989. (Photo by Sean Gallup/Getty Images)

A journalist takes photographs at the site of Thursday's Malaysia Airlines Boeing 777 plane crash near the settlement of Grabovo, in the Donetsk region July 18, 2014. World leaders demanded an international investigation into the shooting down of Malaysia Airlines Flight MH17 with 298 people on board over eastern Ukraine, as Kiev and Moscow blamed each other for a tragedy that stoked tensions between Russia and the West. (Photo by Maxim Zmeyev/Reuters)

Several beaches along South Florida's Atlantic coast line were closed after thousands of sharks were seen migrating in the waters. The sharks were migrating from Boca Raton to Jupiter since the beginning of March, marine biologists told NBC Miami. Photo: A spinner shark swims just offshore on Midtown Beach in Palm Beach on Tuesday. (Photo by Jeffrey Langlois/Palm Beach Daily News)

“A meteor streaked across the sky above Russia's Ural Mountains on Friday morning, causing sharp explosions and injuring more than 500 people (20 had been hospitalized in serious condition), many of them hurt by broken glass. “There was panic. People had no idea what was happening. Everyone was going around to people's houses to check if they were OK”, said Sergey Hametov, a resident of Chelyabinsk, about 1500 kilometres (930 miles) east of Moscow, the biggest city in the affected region”. (Photo by Alexey Bulaew/RIA Nowosti)