Tollinton Market is a long timber-and-brick covered market hall on the Mall, built in 1864 as the central produce market of British Lahore. After a fire and decades of decline it has been restored and now houses temporary art and craft exhibitions rather than a working market.
The building itself — long, low, with cast-iron columns and a pitched timber roof — is the principal interest. It is open during exhibition hours; check what is on before going specifically for it. Combined nicely with the Lahore Museum across the road and Anarkali a short walk south.