The London City Airport was evacuated with all flights cancelled after officials found a 1,100 pound, unexploded World War II bomb near the site at dawn on Tuesday.
Police cleared several streets and are working with officials to defuse the bomb and prevent a potential detonation. Railway stations around the airport have also been closed until the operation is over.
Hundreds of people have been left stranded, missing connecting flights. There was very little information available as alarm bells rang, forcing the evacuation.
This is not the first time dormant World War II bombs have caused chaos.
In 2017, 50,000 people were evacuated from Hanover, Germany in one of the largest operations of its kind when a number of bombs were found around the city.
Just a year before that, the largest post-war evacuation took place in British city of Augsburg when 54,000 people were forced into temporary shelter after the discovery of an unexploded bomb.
But while these evacuations ended safely, World War bombs have caused some deaths and injuries.
In 2010, three bomb disposal experts were killed with three others injured while trying to defuse a 2,000 pound bomb.
Two Belgian construction workers were also killed when a World War I bomb exploded in a field 100 years after it was first fired.
Experts believe there are still hundreds, if not thousands, of unexploded World War bombs scattered across Europe. Officials are in a race against time to find them all, as the bombs become more unstable the longer they lie dormant, which means more evacuations are likely to happen in the future.