They're trying to create the largest "vertical" skydive.
Two-hundred sky-divers need to dive head-first, with their arms and legs locked together in order to break the record.
The skydivers board ten aircraft, climb to 18,000 feet, which requires supplemental oxygen, before diving at speeds up to 240 miles-per-hour.
The attempts started Monday at Skydive Chicago near Ottawa. They plan to continue all week until they break the record.
The previous record was set in 2012 in the Chicago area when 164 divers. There was also an attempt to break the record in 2018, but it was not successful due to unfavorable weather conditions.