Universal Building Sets sets were composed of an assortment of System bricks and building instructions that allowed to build various LEGO models related to a specific subject, in contrast to sets from other themes, such as LEGOLAND, which usually only contained pieces and instructions for one specific model. Other themes that were already present in that era were LEGOLAND and Trains. The Universal Building Sets offered a greater range of a building possibilities and stirred the user's creativity to a larger extent than sets with just a single predefined model.