Zestoa, located in the Urola river valley, is mainly known for the famous medicinal waters of its spa, although it has many other attractive features.

Two stone porticoes at the town's entrance, which are still standing, reveal Zestoa's date of birth, around the 14th century. However, the municipality has some very interesting archaeological sites, such as Erralla, Danbolin, Amalda e Irikaitz, and specially Ekain, which reveal a much earlier presence of humans in this area.

In the city centre we can see some remarkable monuments, such as the 16th-century church, and the City Hall, from the 17th century. Thanks to the foundries built in the 15th to 18th centuries, many ancestral homes were constructed, which can still be seen. The most significant are Portalekua and Lizentziadokoa, both from the 16th century.

In the outskirts, we find the Gothic palace of Lili, and a spa founded in 1804, although the properties of its waters were known since much earlier. It was turned into a hotel in 1930.

In addition, the hermitage of San Juan, and the houses of Lizarraitz are excellent examples of the popular architecture found in this municipality.