Hundreds of thousands of people from Australia to Paraguay joined the biggest day of climate change activism in history on Sunday, telling world leaders gathering for a summit in Paris there is "No Planet B" in the fight against global warming.In the French capital, where demonstrations were banned by the authorities after attacks by Islamic State militants killed 130 people on Nov. 13, activists laid out more than 20,000 shoes in the Place de la Republique to symbolize absent marchers on the eve of the summit.Among the high heels and sandals were a pair of plain black shoes sent by Pope Francis, who has been a vocal advocate for action to prevent dangerous climate change, and jogging shoes from U.N. Secretary-General Ban Ki-moon.One activist, dressed in white as an angel with large wings, held a sign saying "coal kills". About 10,000 people joined arms to form a human chain through Paris along the 3-km (2-mile) route of the banned march, organizers said.More than 2,000 events were held in cities including London, Sao Paulo, New York and Asuncion, Paraguay, on the eve of the Paris summit which runs from Nov. 30-Dec. 11 and will be attended by about 150 heads of government."Over 570,000 people called with one voice for global leaders to deliver a 100 percent clean energy future at the Paris summit," said Emma Ruby-Sachs, campaign director of Avaaz, one of the organizers.Around the world, activists marched, dressed as polar bears or penguins at risk from melting ice, or chanted slogans such as "climate justice".Organizers said that 570,000 people so far had taken part in rallies worldwide and that they expected demonstrations including in Ottawa and Mexico City later in the day to push the count above 600,000.The nearly two-week conference comes more than two weeks after the Paris attacks. A state of emergency was imposed in France after the carnage, and marches have been banned.Here are some of the rallies that took place in Europe on Sunday.PARISThousands of demonstrators gathered in central Paris and formed a human chain along the route of a long-planned protest march that was banned by the French government in a security crackdown following the Nov. 13 Paris attacks. Nearby, thousands of shoes, some decorated, were placed at the Place de la Republique to symbolize the many feet that could not march because of the ban.But violence erupted as the day progressed with several hundred people, some of them masked, throwing objects at riot police blockading the square in a bid to break through.Interior Minister Bernard Cazeneuve said 174 people were jailed for possible charges. He said, separately, that 26 people have been placed under house arrest, stressing they weren't militants but people known for violence in the past.Some protesters chanted "a state of emergency is a police state."Paris police chief Michel Cadot said that a group of 200 or 300 people violated a ban on protests under the country's state of emergency. Cadot said that the group lobbed glass bottles and other projectiles, including candles set out in homage to the 130 victims of the extremist attacks. Shoes laid out at the earlier ceremony also were tossed about. Police fired numerous rounds of tear gas to disperse the group.President Francois Hollande denounced the violence by a minority as "scandalous," both because the clashes were caused by "disruptive elements" that have nothing to do with environmental activists and because they occurred at Place de la Republique, which has been a memorial square for the victims Paris attacks. He said "everything will be done" to ensure they are not present during the conference.Prime Minister Manuel Valls also denounced the violence in a tweet, saying that respecting the square, used to pay homage to attack victims, "is to respect the memory of victims."It was not immediately clear if those involved in the violence were from a specific group. A known climate pressure group, 350.org, said the protesters were "unaffiliated with the climate movement and broke "the non-violent pledge that every group involved in the climate coalition" signed off on.The protests were held ahead of the critical global warming talks outside Paris beginning on Monday.SPAINThousands of people took to the streets of several Spanish cities to demand a commitment from world leaders to halt climate change in what organizers are calling the largest pro-environment mobilization in Spain to date.Friends of the Earth and Greenpeace both said around 20,000 protesters marched between Cibeles and Puerta del Sol in Madrid, while thousands also marched through cities such as Barcelona, ??Bilbao, Las Palmas, Murcia, Pamplona, ??Seville, Valladolid and Zaragoza.At a march through the streets of Madrid, one banner read, "I am marching for my children and grandchildren" and another said "We don't have a planet B.""Well, to be honest we don't expect much (from the politicians). That's why we are here," said Incarnacion Florin. "We have to do something. It must make a difference."The gatherings were organized by more than 400 Spanish non-governmental organizations and other groups. Others around Spain were organized by the Alliance for the Climate and call on world leaders to reach "a fair, ambitious and binding agreement to avoid the worst consequences of climate change and accelerate the transition toward renewable sources of energy by 2050.LONDONThousands of people marched through London, urging world leaders not to blow their chance to take strong action on climate change.Actress Emma Thompson, designer Vivienne Westwood and Labour Party leader Jeremy Corbyn are among demonstrators urging politicians to strike a binding agreement at climate talks in Paris.Corbyn told the crowd that the talks were "an enormous opportunity" to tackle "pollution, climate change, inequality, environmental refugees, war refugees and resources wars. If we are to make a real difference in Paris, all these issues have got to be thought about and addressed."Thompson said that climate change, once seen as a fringe cause, was now "the issue of the 21st century."Numbers at the London march from Hyde Park to the Whitehall government district were swelled by the ban on a protest march in Paris.GERMANYAbout 4,000 people held a rally in the German capital, marching from Berlin's train station to the Brandenburg Gate to listen to speeches and music.The protesters called on the delegates at the Paris conference to set ambitious targets, using an array of signs, including a picture of a polar bear with "Save Me" written on it, or simply "Stop Global Warming.""I hope that there is a climate agreement that really helps, but I fear actually that the countries and government leaders will only agree to something that won't help, primarily a weak agreement that will not help the living conditions on this planet," said Dr. Anton Hofreiter, member of the Green Party in Germany's parliament.