Eurostar trains to London and all trains heading to northern France were brought to a halt Friday following the discovery of an unexploded World War II era bomb on tracks leading to the nation’s busiest station.

The police successfully defused the explosive device, which weighs more than 1,000 pounds and was found near tracks north of the French capital during landscaping work.

All 32 trains scheduled to run between London and Paris on Friday have been cancelled, wrecking travel plans for thousands of passengers. But extra services have been added to Saturday's timetable.