Bulk metallic glass forming melts are viscous liquids if compared with pure metals and conventional alloys. They show an intermediate kinetic fragility and small thermodynamic driving force for crystallization leading to sluggish crystallization kinetics, leaving time for good glass forming ability and bulk casting thickness. We can relate the kinetics to the thermodynamics of the supercooled liquid via the Adam-Gibbs equation. The kinetic fragility is also connected to the structural changes in the liquid and can be quantitatively linked to the robustness of medium range order in the supercooled liquid with increasing temperature. Liquid-liquid transitions from fragile behavior at high temperature to strong behavior at low temperature in the supercooled liquid and in the vicinity of the glass transition emerge as a common phenomenon .