Market Place. The Market Place was once entered from Highgate by two lanes. Cheapside and Mercers' Lane. Between them stood shops with the market cross and the pillory outside them in Highgate. The stocks stood behind the shops and the Moot Hall, serving as town hall and court room, was on the corner of Mercers' Lane. In 1754 the shops were replaced by a chapel, a covered market and, underground, the "Black Hole", a dungeon used until 1836.