Two friends stumbled upon the unexpected on Sunday when their cycle trail through the countryside led them right through the middle of an enormous illegal party.

The video shows them cycling in Devil's Dyke, a popular scenic location in Sussex, England. Soon they encounter hundreds of revellers and cars crowded around the main dance area, with techno music booming in the background.

They don't appear to be the only ones not invited either - a pair of hikers with backpacks look equally out of place at this makeshift music festival.

The Metro reports that police estimate the number of attendees at 2,000, along with 400 vehicles. The rave was, as the cyclist guesses, 'not official,' though local police did not intervene due to weather conditions and a lack of officers.