My personal favorite area for climbing in Colombia. Located in Chicamocha Canyon this spot boasts more than 300 routes with powerful pumpy roof moves on incredible sandstone over the edge of an incredible canyon. A visit to Colombia is not complete without a visit, with or without climbing.
From Bucaramanga take the bus to Mesa de Los Santos and ask to be dropped off at the Refugio la Roca, which is also the name of the hostel located above the crag.
I (and lonley planet) recommend staying at the Refugio la Roca. It is an incredible hostel located on top of the crag with accomodation looking over the canyon costing starting at about 10 USD