Ano Viannos, usually known simply as Viannos, is a historic small town and the administrative centre of the province of Viannos in southeastern Heraklion. It is built at an altitude of approximately 550 metres, on the southern slopes of the Dikti range, overlooking a fertile region with olive groves and small mountain villages. The local economy is mainly connected with agriculture, olive oil production and livestock farming.

A short distance west of the modern town stood the ancient city of Viennos, from which Viannos takes its name. The ancient city minted its own coins, depicting the goddess Artemis and a flower together with the inscription VIANI.

Viannos was destroyed during the revolutions of 1822 and 1866. The most tragic chapter in its history was written in September 1943, when the Nazi occupation forces carried out mass executions and destroyed villages in the provinces of Viannos and western Ierapetra. Between 14 and 16 September, 401 civilians were murdered, while the total number of victims in the villages of Viannos during the occupation reached 461. The history of the Viannos Holocaust is presented at the memorial and museum at Seli of Amiras.

Visitors can walk through the narrow lanes of Ano Viannos and stop at the central square beneath its large plane tree. The town was the birthplace of the writer and journalist Ioannis Kondylakis, who is regarded as the father of the Greek newspaper chronicle. Near the square are the restored watermill and the Folklore Museum of Viannos.

Numerous old churches survive within and around the town. Particularly important is the Church of Agia Pelagia, with remarkable frescoes dating from the 14th century. Other churches include Michael the Archangel, the Virgin Mary, Agia Marina, Agia Aikaterini and Agios Dimitrios. A short distance outside Viannos stand the historic monastery of Agia Moni and the frescoed Church of Agios Georgios.