Ladder

A ladder was a tool used to climb to higher areas. Rope-ladders were often attached to helicopters and other vehicles capable of flight. (TV: The Invasion, World Enough and Time)

The Third Doctor and Tom Streeter used a ladder in Africa to enter the depths of a Volcano. (COMIC: Trial of Fire)

A board game entitled Snakes and ladders used illustrations of ladders to signify moving up in the board. (PROSE: Time and Relative, et. al)