Query: Where is University College London, or UCL, ranked among the world's best colleges and universities?
Context: A number of world-leading education institutions are based in London. In the 2014/15 QS World University Rankings, Imperial College London is ranked joint 2nd in the world (alongside The University of Cambridge), University College London (UCL) is ranked 5th, and King's College London (KCL) is ranked 16th. The London School of Economics has been described as the world's leading social science institution for both teaching and research.