A lightning-sparked apartment fire displaced 21 people in Thornton on Monday, according to the Thornton Fire Department. Fire crews were fighting a structure fire at Madison Park Apartments, 3351 E. 120th Ave., at 3:56 p.m., the department said in a post on X. Firefighters cleared the scene as of 6 p.m. after determining the fire was started by lightning, according to the department.