This October 25, 2014 photo provided by the U.S. Geological Survey shows lava flow advancing across the pasture between the Pahoa cemetery and Apa'a Street, engulfing a barbed wire fence, near the town of Pahoa on the Big Island of Hawaii. Dozens of residents in this rural area of Hawaii were placed on alert as flowing lava continued to advance. Authorities on Sunday, October 26, 2014 said lava had advanced about 250 yards since Saturday morning and was moving at the rate of about 10 to 15 yards an hour, consistent with its advancement in recent days. The flow front passed through a predominantly Buddhist cemetery, covering grave sites in the mostly rural region of Puna, and was roughly a half-mile from Pahoa Village Road, the main street of Pahoa. (Photo by AP Photo/U.S. Geological Survey)

“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

Boys walk home for lunch from school in the village of Kogelo, west of Kenya's capital Nairobi, July 16, 2015. U.S. President Barack Obama visits Kenya and Ethiopia later this month. His ancestral home of Kogelo is home to Sarah Hussein Obama, his step-grandmother. The Kenyan village, burial place of Obama's father, features an open-pit goldmine, a pork butcher's, a school named after their most famous son and outdoor market stalls. Villagers get around by motorbike taxi or on foot while a donkey-cart transports water. Children, some of them named Obama in honour of the President, walk to and from school together. (Photo by Thomas Mukoya/Reuters)

Historical re-enactor Andreas Wenzell dresses as Britain's King Richard the third in a living history camp during an anniversary event for the Battle of Bosworth near Market Bosworth in central Britain, August 23, 2015. The Battle of Bosworth took place in 1485 during the War of the Roses between the House of Lancaster and the House of York. King Richard III was defeated by Henry Tudor marking the end of Plantagenet rule and the beginning of the Tudor dynasty. (Photo by Neil Hall/Reuters)

A period of relative stability has put the Iranian capital No1 on the list of world cities that have achieved biggest improvements in liveability over the past five years, as calculated by the Economist Intelligence Unit. The “most improved” top 10 contains some unexpected names. So, eg, the fourth place: Abidjan, Ivory Coast. Latest ranking: 128; Ranking five years ago: 131; Five-year index movement: 3.8%. Here: A supporter of Ivory Coast president Alassane Ouattara campaigns in a market in the city’s Koumassi quarter. (Photo by Sia Kambou/AFP Photo)

An ethnic Kayaw couple Mu Htoo and her husband Htaw Eili rest at their home at Htaykho village in the Kayah state, Myanmar September 12, 2015. With about 30,000 members, the Kayaw are one of the smallest ethnic minorities among Myanmar's 135 groups. Their village has for decades been off-limits, as armed rebels fought the military before a recent ceasefire stopped the bloody conflict here. The rebels in the area have put down their guns and taken to the hills to grow rice and corn, but slash-and-burn cultivation methods mean they struggle to find new places to farm. (Photo by Soe Zeya Tun/Reuters)

A child dressed in an imitation dress of army soldier enjoys a cold drink during a religious procession in Amritsar, India, 15 December 2015. The religious procession was taken out on the eve of the martyrdom day of the 9th Guru or Master of the Sikhs Sri Guru Tegh Bahadur Ji. Guru Tegh Bahadur was executed for not converting to Islam on the orders of Mughal Emperor Aurangzeb in Delhi in 1675 AD. The place of this occurrence is called Gurudwara Sis Ganj at Delhi. Guru Tegh Bahadur the youngest of the five sons of Guru Hargobind was born in Amritsar in 1621. (Photo by Raminder Pal Singh/EPA)

Mah Chan, a Long Neck Padaung hill tribe woman weaves a scraf for sale to tourists in a small village where 30 familes live July 13, 2006 in Chiang Dao, Thailand. All the Long Neck villages are set up for tourists and just over a year ago the hill tribe members were hand picked to move closer to Chiang Mai from more remote communities so that they could be more accessible. The Padaung women famously wear brass rings around their necks, beginning at five-years-old, to distort the growth of their collarbones and making them look like they have long necks. They are originally from eastern Burma near the Thailand border. (Photo by Paula Bronstein/Getty Images)