Canadian Prime Minister Justin Trudeau kicked off celebrations on Saturday to mark the country's 150th birthday amid heavy security as many citizens braved incessant rains and long delays to reach the main site in the nation's capital, Reuters reported. About 500,000 people were expected to be in Ottawa for the long-anticipated Canada Day festivities, which features a large outdoor celebration in front of the national Parliament, complete with acrobats, fireworks and musicians, including singer Bono and other members of Irish rock band U2. Trudeau, accompanied by Britain's Prince Charles, shook hands with some of the thousands of revelers who converged on Canada's capital Ottawa for the festivities. "Canada is a country made strong not in spite of our differences but because of them," Trudeau told the gathering. "We don't aspire to be a melting pot indeed, we know true strength and resilience flows through Canadian diversity." Some cities are celebrating in more unusual ways. Toronto, Canada's largest city, will have a giant rubber duck floating in its harbor, while Calgary will have a "living flag" composed of people wearing red and white. Security was already ramped up in the days ahead of the celebration and party-goers must contend with road closures and concrete barriers across entrances into Parliament Hill, located in downtown Ottawa. Heavy downpours prompted Ottawa firefighters to pump water off the grounds on Parliament Hill and the Ottawa Fire Service urged citizens to follow safety instructions. National and local police were also out in force, with security top of mind for many Canadians in the wake of fatal attacks in Europe. Saturday marks the 150th anniversary of the day Canada officially became a country. Britain had ruled it before 1867.