Final answer:
In 2003, Britain's antiwar protestors set a world record for the largest simultaneous protest against a war.
Step-by-step explanation:
In 2003, Britain's antiwar protestors set a world record for the largest simultaneous protest against a war. Approximately 1.5 million protesters marched through the streets of London on February 15, 2003, to express their opposition to the proposed invasion of Iraq by the United States and its allies. This protest was part of a global movement against the war, with demonstrations taking place in cities around the world.