Thousands of people are lining the streets of central London to witness the funeral procession of former British Prime Minister Margaret Thatcher.
World leaders and dignitaries from 170 countries are attending the Wednesday funeral amid heavy security at St. Paul's Cathedral.
Guests include Britain's Queen Elizabeth and Prime Minister David Cameron. Former U.S. Secretary of State Henry Kissinger and ex-Vice President Dick Cheney are also in attendance, as are prime ministers from 11 different countries.
Mrs. Thatcher's union flag-draped coffin is being transported to the cathedral by a horse-drawn gun carriage along a central London route lined by members of the British armed forces.
More than 4,000 police have been deployed in London as part of a security operation that was increased following Monday's deadly bomb attacks in Boston.
Mrs. Thatcher died from a stroke nine days ago at the age of 87. Britain's first and only female prime minister, she became one of the country's most influential modern-day leaders during her time in office from 1979 to 1990.
Dubbed the Iron Lady, Mrs. Thatcher was a stern conservative who broke the power of British unions, eliminated many government subsidies and enabled a far greater role for private enterprise.
She led Britain through its 1982 war with Argentina over the Falkland Islands, strongly opposed European integration and built a close "special relationship" with U.S. President Ronald Reagan that helped spur the downfall of Soviet communism.
She leaves behind a divisive legacy in Britain. During her funeral Wednesday, some of her political opponents are holding a demonstration along the route of her funeral procession.
She is being given a funeral with full military honors - a step short of a state funeral - in accordance with the wishes of her family. The event is thought to be London's most significant political funeral since the death of ex-Prime Minister Winston in 1965.
The chimes of London's historic Big Ben are being silenced for the duration of the funeral service.