The end of the world seemed near Monday in Copenhagen. Four horsemen of the Apocalypse rode through the streets of this Danish city. For those who are now on the verge of panic, calm down: The riders were "only" part of a Greenpeace protest, but they nevertheless meant to warn delegates at the U.N. climate conference that failure to broker an ambitious climate protection deal at the U.N. climate conference could have catastrophic effects for the world.
Greenpeace and other organizations have staged several demonstrations over the past few days, with tens of thousands of activists taking the streets of Copenhagen Saturday and Sunday to demand strong action to stop climate change.
The activists marched from the city center to the conference venue in a largely peaceful demonstration; however, toward the end of Saturday's march, masked protesters threw stones through stock exchange and Foreign Ministry buildings in the city.
Danish riot police moved in and cut off a large portion of the protesters, detaining around 1,000 of them. They were held in what critics say were inhumane conditions -- some of them forced to sit on the icy ground for hours -- but have since been released.
The Environmental News Service reports that "some people have spent five hours handcuffed to benches without food, water or access to toilet facilities. Several people fainted while handcuffed in the corridor for hours. Volunteers from the people's kitchens requested to be able to provide food for the hundreds of prisoners, but were refused by police authorities."
Police Sunday broke up what authorities said was an unauthorized demonstration, detaining around 200 activists in the process.
A Danish law allows police to arrest and hold protesters for 12 hours without court orders in case authorities feel the demonstration could turn violent. The law has been harshly criticized by NGOs.
Confrontation continued Monday, when unknown individuals torched three cars owned and branded by Danish utility Dong Energy in the city center -- just a few hours before a demonstration near the company headquarters. Dong is controversial with climate activists because it runs coal-fired power stations.
The demonstrations happened halfway through the Dec. 7-18 summit attended by some 15,000 representatives from 192 countries.
U.S. President Barack Obama, Chinese Prime Minister Wen Jiabao and more than 100 other world leaders are expected to arrive here later this week to try to broker a climate-protection deal to succeed the Kyoto Protocol, which runs out in 2012.
Officials hope the deal will include binding carbon dioxide emissions reduction commitments from the world's major emitters -- including the United States, India and China -- as well as dozens of billions of dollars in financial aid to poor nations.
Notable deaths of 2014 [PHOTOS]