For weeks, the primatologists had followed a group of Grauer’s gorillas over rugged terrain – hacking through dense rainforest; following knife-edged ravines; and crossing a nearly impenetrable mountainous landscape in the eastern part of the Democratic Republic of the Congo (DRC).

MEXICO CITY – On bad days, you can smell the stench from a mile away, drifting over a nowhere sprawl of highways and office parks.

The legal commercial exotic animal trade is a booming enterprise that ships ornamental fish, mammals, birds, reptiles and amphibians around the world. These pets, livestock and other animals can carry unexpected infectious diseases from their homelands. If these non-native species escape or are released to the wild, they can create epidemics among susceptible endemic wildlife.

Frank Morton has been breeding lettuce since the 1980s. His company offers 114 varieties, among them Outredgeous, which last year became the first plant that NASA astronauts grew and ate in space. For nearly 20 years, Morton’s work was limited only by his imagination and by how many different kinds of lettuce he could get his hands on. But in the early 2000s, he started noticing more and more lettuces were patented, meaning he would not be able to use them for breeding.

AGADEZ, Niger — The world dismisses them as economic migrants. The law treats them as criminals who show up at a nation’s borders uninvited. Prayers alone protect them on the journey across the merciless Sahara.

The United Nations Environment Program is highlighting the battle by Iraqi forces to reclaim Mosul from the Islamic State as the latest instance in the complex but very real linkage between military conflicts around the world and extreme environmental degradation.

“By 2050 the world urban population is expected to nearly double, making urbanization one of the 21st century’s most transformative trends.” -Draft “Quito Declaration on Sustainable Cities and Human Settlements for All,” September 2016

Early on the morning of Sept. 29, according to India’s Defense Ministry and military, Indian forces staged a “surgical strike” in Pakistan-administered Kashmir that targeted seven terrorist camps and killed multiple militants. Pakistan angrily denied that the daring raid took place, though it did state that two of its soldiers were killed in clashes with Indian troops along their disputed border. New Delhi’s announcement of its strike plunged already tense India-Pakistan relations into deep crisis. It came 11 days after militants identified by India as members of the Pakistani terrorist group Jaish-e-Mohammed killed 18 soldiers on a military base in the town of Uri, in India-administered Kashmir.