The Eidgenössische Technische Hochschule (ETH) Zurich is one of the world's leading technical universities, and its main building — the Hauptgebäude, on the Polyterrasse above the old town — is one of the grandest 19th-century buildings in the city. Built by Gottfried Semper in 1864 in a confident Italian Renaissance style, the building is open to visit during the day and the rooftop terrace behind it gives one of the finest panoramic views in central Zurich, free and very rarely crowded.
The lobby and main staircase under the entrance dome are worth a quick visit; the ETH library sometimes hosts small exhibitions of rare books or scientific instruments from its collection. The Polyterrasse café — a sunny outdoor terrace — is a quieter alternative to the lakeside bars for an evening drink. Reach it on the Polybahn funicular from Central in two minutes.