Although essentially a building site, the completed sections and museum may be explored at leisure. Guided tours (50 minutes, €24) are offered. Alternatively, pick up an audio tour (€7), for which you need ID. Enter from Carrer de Sardenya and Carrer de la Marina. An extra €14 (which includes the audio tour) will get you into lifts that rise up inside the towers in the Nativity and Passion facades. The two facades, each with four sky-scraping towers, are the sides of the church. It's best to pre-book all tickets online, and essential for tower tours.