LEGO themes are specific categories or styles of LEGO sets that share common elements, characters, and storylines. Popular themes include LEGO City, which focuses on urban life and emergency services, and LEGO Star Wars, which features characters and vehicles from the iconic film franchise. Each theme offers unique building experiences and often includes minifigures and accessories related to the theme. Other notable themes include LEGO Friends, aimed at a younger audience with a focus on friendship and adventure, and LEGO Technic, which emphasizes advanced building techniques and mechanical functions. These themes allow builders to explore different worlds and narratives while enjoying the creativity of LEGO construction.