It's taken roughly five months, but a massive iceberg has separated from Antarctica's Pine Island Glacier. According to NASA's Earth Observatory, the estimated size of this iceberg, named B-31, is around 660 square kilometres (33 km long by 20 km wide) – a city-sized block of ice that has slowly migrated away from the continent, and is now floating out to sea. Take a look at some massive icebergs afloat in the oceans. Photo: File photo of an iceberg floating near a harbour in the town of Kulusuk, east Greenland August 1, 2009. (Photo by Bob Strong/Reuters)

A donkey carrying sacks of coal walks through the narrow tunnels of a coal mine, in Choa Saidan Shah in Punjab province April 29, 2014. Coal miners in Chao Saidan Shah use donkeys to transport coal from the depths of the mines to the surface. (Photo by Sara Farid/Reuters)

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)

Israeli soldiers detain a protester during a demonstration by Palestinians protesting against the Israeli-built West Bank separation barrier and calling for the right of return for Palestinian refugees, in the northern West Bank city of Tulkarem, on May 31, 2014. (AP Photo/Nasser Ishtayeh)

“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

Britain's Red Arrows airplane display team perform during D-Day commemorations in Portsmouth in southern England on June 5, 2014. Several hundred surviving veterans of the 1944 D-Day landings are commemorating the 70th anniversary of the mission on both sides of the English channel. (Photo by Carl Court/AFP Photo)

A resident douses passengers riding in a public motorcycle cab with water, during St. John the Baptist Feast Day celebrations in San Juan city, metro Manila June 24, 2014. Residents participate in an annual city-wide waterfest in honour of their patron Saint John the Baptist. (Photo by Romeo Ranoco/Reuters)

The bare feet of a devotee are pictured as she takes a dip at the Bagmati River during the “Bol Bom” (Say Shiva) pilgrimage in Kathmandu July 21, 2014. The faithful, chanting the name of Lord Shiva, run about 15 km (9 miles) barefooted toward Pashupatinath temple seeking good health, wealth and happiness. (Photo by Navesh Chitrakar/Reuters)