The Feira de São Mateus is one of the oldest and largest fairs in Portugal, held annually in August and September in Viseu. It has operated since 1392 — first as a church market, then as a regional agricultural and craft fair, now as a large popular festival with food, wine, music, and commerce. The scale is striking: thousands of stalls spread across the Parque de Exposições, selling everything from regional crafts to furniture to cars.
The food and wine section is the most interesting for visitors. Dão wines are the obvious draw, but the fair also brings together producers of smoked meats, Serra cheese, traditional pottery, and handwoven textiles from across Beira Alta. The festival programme includes concerts, folk performances, and regional competitions. If you're in central Portugal in August or early September, the fair is worth a visit for the atmosphere alone.