Sitting beneath a man-made slope above Faliron Bay, and shaded by a 'Magic Carpet' roof covered with solar panels, this stunning Renzo Piano building, completed in 2016, is home to the Greek National Opera and the main branch of the National Library. It's surrounded by a beautiful big park and hosts an impressive range of events and exhibitions, several of which are free.
In addition to regular public transport, you can use a free shuttle bus, departing from Syntagma at Ermou. It runs at least eight times a day on weekdays, and every 30 minutes from 9.30am to 9.30pm on weekends. The last shuttle back is 11.30pm Monday to Thursday and midnight Friday to Sunday.