Terceira Island contains four stratovolcanoes. Historically active
Santa Barbara volcano at the western end of the island is truncated by two
calderas. The youngest of these formed about 15,000 years ago. Guilherme Moniz
caldera lies along the fissure zone immediately to the south, and 7-km-wide
Cinquio Picos caldera at the SE end of the island is the largest in the Azores.
With an elliptical shape, Terceira has an area of 381.96 km2. Its length is 29
km and its maximum width 17.5 km. A plateau, cut by the gentle slopes of the
Cume hills, dominates the western end. The central area is marked by the large,
deep crater called Caldejra de Guilherme Moniz and by many craters with small
lakes.
The municipal seat is located in "Angra do Heroísmo”, where the The
"Paços do Concelho" (City Hall), a majestic construction of the 19th
century, is an important example of the rich patrimony of Angra.
The network of streets of a town that is a monument in itself. Angra do Heroísmo
was entitled as world-wide patrimony city. The colourful "impérios"
or chapels that bear witness to popular devotion. The walls of a castle that was
a royal prison. The constant presence of history. The gentle ondulation of a
green countryside. The white triangle of the typical chimneys. Sides of the
attractive and colourful prism that is Terceira.