Abbi Bell's marathon trek in Mongol Derby ends on Day 7

JACKSONVILLE, Fla. – Abbi Bell had never done anything quite like the Mongol Derby, and made it more than halfway through the event billed as the world's longest and toughest horse race. 

The Middleburg resident covered roughly 412 miles through the first seven days of the endurance horse race before retiring from the event Tuesday. 

Bell opened the day tied for 21st place before a rugged day claimed a large portion of the field. A total of 11 riders retired during or after Tuesday’s leg. 

The event finishes Friday, the last of the 600-mile course that riders cover over 10 days. 

The Mongol Derby is an event that draws riders from all over the world. Horse racers ride semi-wild horses over 600 miles and change horses roughly every 25 miles. The event is built on Genghis Khan’s horse messenger system that developed in the 13th century.