A method of assembling a structure, such as a wind turbine, is disclosed. The method comprises a step of providing a lifting arrangement comprising a gantry disposed over and/or directly above a rail, and lifting means coupled to the gantry. The method further comprises stacking portions of the structure by: conveyably disposing a first portion of the structure relative to the rail; lifting a second portion of the structure using the lifting means; disposing the first portion underneath the second portion by conveying the first portion along the rail; and lowering the second portion onto the first portion. Also disclosed is a corresponding system for assembling a structure, such as a wind turbine, and corresponding clamping and/or gripping system.