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Denis Voronenkov, a former Russian lawmaker and Kremlin critic who fled to Ukraine last year, was shot dead in Kiev. CNN's Brian Todd has the latest.

A zoo in the Czech Republic has begun removing the horns of all its rhinos, saying it is better to leave the animals with stumps than risk them being killed by poachers.

The London attacker, Khalid Masood, is believed to have acted alone in carrying out what UK officials are calling a "copycat," or "ISIS-inspired" attack.

For the first time, researchers have estimated what percentage of cancer mutations are due to environmental and lifestyle factors, hereditary factors and random chance. Overall, 66% of the genetic mutations that develop into cancer are caused by simple random errors occurring when cells replace themselves, according to a new study published in the journal Science.

Henry Obiefule has been making others laugh with his internet skits, but now he'll be laughing all the way to the bank after signing a million dollar deal.

Police have launched a "full counter-terrorism investigation" after an attacker rammed a car into crowds of people and stabbed a police officer on Parliament grounds.

In some of the vast, remote areas of the Navajo Reservation, supplies and services can be hours away. In winter, temperatures can dip to zero.

Congress is botching the investigation into Russia's meddling in US election and whether Trump and associates involved, says Page Pate. A competent and credible investigator needs to cut through the partisan jockeying.

CNN Hero Linda Myers shows how her nonprofit helps Native American elders in remote areas of Arizona and Utah stay warm through the winter.

For three decades, Linda Myers and her nonprofit have brought life-saving supplies to an estimated 3,000 elders in need on the Navajo Reservation.

This week's vote on the health care plan will be a key moment in the political history of the Trump presidency. A huge amount of political capital, for everyone involved, rests on the outcome of the vote in the House. The final decision will also have massive policy implications for the President and both parties on Capitol Hill.

An educator accused of using his political clout to curry favor with Japanese politicians, including the first family, is set to address parliament Thursday.

Andy Warhol's personal photographs from his trip to Beijing and Hong Kong in 1982 are arguably the most famous holiday snaps of all time.

Once again, a driver has plowed into a crowd of pedestrians, turning a car into a lethal weapon.

It's a depressingly familiar tale. A vehicle slams into a group of pedestrians in a Western city and the terrorist driving the car then uses a knife to inflict further damage and is soon shot by police.

There was an unexpected face among the first responders to Wednesday's attack near the House of Parliament in London. Tobias Ellwood, a Conservative Member of Parliament, was seen tending to an injured man lying outside of Westminster Palace.

Watch and hear firsthand accounts of the Parliament attack in London.

British lawmakers were locked down inside Parliament on Wednesday as a frightening scene unfolded outside.