Workers carry out maintenance on the transmitter towers of the 1,127ft (344m) John Hancock Center in Chicago.

Collaboration between the US and Russia on the International Space Station (ISS) could be jeopardised as tensions between the two nations create political disputes.

Russian aid lorries are heading for Ukraine although it is unclear if officials will allow them to travel past the border.

Israel and the Palestinians have agreed to extend their ceasefire by five days. The BBC's Yolande Knell reports.

There has been a fourth night of violence on the streets in Missouri after an unarmed black teenager was shot dead by police. Freelance Journalist Mariah Stewart describes what she saw on Wednesday evening.

A deluge in the New York area has broken rainfall records, causing flooded roads and traffic chaos.

Pope Francis has landed in South Korea for a five-day visit, his first trip to Asia since he became pontiff

The BBC's Sharanjit Leyl tours the USS Michigan, a nuclear submarine which includes three women in its 170-strong crew.

Caroline Wyatt reports on the refugees arriving in Iraqi Kurdistan after fleeing their homes across Mount Sinjar.

Brazilian presidential candidate Eduardo Campos has died in a plane crash in the city of Santos, officials say.

A landslide in Switzerland derails a train at the top of a ravine, injuring several passengers and leaving one carriage hanging over the precipice.

An Iranian mathematician working in the US has become the first ever female winner of the celebrated Fields Medal.

Tens of thousands of security personnel have been deployed in the Pakistani capital Islamabad ahead of an anti-government march, led by the opposition politician Imran Khan.

President Obama has urged the community in St Louis, Missouri, to remain calm following the killing of an unarmed teenager that has sparked two days of unrest.

The outlook for Australia's Great Barrier Reef is poor, a new report says. The BBC's Matt McGrath said the Great Barrier Reef posed a "difficult economic dilemma" for the Australian government.

Security camera footage captures the moment a wall of water gushes through a Nebraska hospital.

The deadly virus Ebola has claimed a third victim in Nigeria, taking the overall death toll to over 1,000 people.

The BBC's Barbara Plett Usher meets Yazidi Americans who have dropped everything to keep Washington's attention on the tragedy in their homeland.

Immigration centres in southern Spain are overflowing after a wave of small boats and dinghies carrying more than 1,200 migrants made it to the Spanish mainland.

Ukrainian refugees have flown from Crimea to the Russian city of Ulyanovsk, according to Russian television station Channel 1.