In this review, the intriguing properties of clathrate hydrates shall be discussed, as well as their environmental impact and prospects for energy exploitation in industry. In particular, the anomalous behaviour of hydrate thermal conductivity will be described, as well as challenges in understanding nucleation and kinetics. Particular attention shall be devoted to recent progress and advances in the molecular simulation of clathrate hydrates, as well as elusive challenges thereof, which underpin our molecular-level understanding of clathrate behaviour, especially in terms of microscopic mechanisms of thermal conduction, nucleation, hydrogen storage and prospects for carbon sequestration. (C) 2014 Elsevier Ltd. All rights reserved.