Stavros Niarchos Foundation Cultural Center

When a Greek shipping dynasty decides to give back, they don't do things by halves. The Stavros Niarchos Foundation spent $861 million building this complex — designed by Pritzker Prize-winning architect Renzo Piano — and then donated the entire thing to the Greek state in 2017. It houses the National Library of Greece and the Greek National Opera under one roof, surrounded by 170,000 square meters of landscaped parkland. It is, by any measure, the most ambitious cultural building project in modern Greek history.

Piano's design concept was to create an artificial hill — a building that rises out of the ground like a dislodged piece of the Earth's crust. The roof of the opera house and library forms a sloping landscape that visitors walk up, ultimately reaching a canopy topped with 10,000 square meters of photovoltaic cells that generate 1.5 megawatts of power, making the building largely energy self-sufficient during normal hours. It was the first public building in Greece to achieve Platinum LEED certification.

The opera house seats 1,400 in the main auditorium plus 400 in a flexible black box theater. The library's reading room sits at the top of the building, entirely encased in glass, with 360-degree views of Athens, the Saronic Gulf, and the mountains. Below, a canal and reflecting pools create a water feature that runs through the park, which includes an olive grove, running paths, playgrounds, and a summer cinema.

Located 4 kilometers south of central Athens in Kallithea — a working-class neighborhood that the SNFCC has single-handedly transformed — it's best reached by a dedicated bus or the coastal tram. Come on a Sunday when Athenian families spread out on the sloped lawn for picnics, kids run through the water features, and the opera house is hosting something free. It feels like the Athens of the future.