The Hoyos de Bandama winery is the only winery in the Monte area of northeast Gran Canaria that is open to walk-ins, but you do need to book in advance for a full winery tour and tasting session. 

Visit Bandama at dawn when the caldera is full of mist and the picon lava is glowing, and it's one of the island's great spectacles. Visit any time and there's plenty to do and see from a secret bunker to classy wineries.