History buffs and families alike have the opportunity to time travel this month, as Knapp Heritage Park marks its 20th anniversary with a celebration of pioneer life. The event, taking place in Downtown Arlington, promises a day of learning and fun without a price tag. According to the City of Arlington, the Arlington Historical Society invites the public to join the festivities from 10 a.m. to 5 p.m. on Saturday, Sept. 28.