An estimated 200 people in the Romanian village of Clinceni have unfurled what the Guinness World Records say is the largest flag ever made.
The flag, measuring 349m (1,145ft) by 227m (744ft) and weighing five tonnes, was spread over seven acres of an airfield south of the capital, Bucharest.
It was broadcast live on national TV.
Work on the enormous red, yellow and blue tricolor began two months ago and took hundreds of hours to complete.
An estimated 44 miles (70km) of thread was needed.
Prime Minister Victor Ponta and other members of the Romanian government attended Monday's event, which was celebrated with an air show.
The previous record for the world's largest flag was held by Lebanon.