The Terra Nostra Garden is the headline attraction of Furnas: about twelve hectares of mature trees, ponds, streams and formal beds, organised around a small lake and a large iron-rich thermal pool. The collection includes more than 2,000 species, with strong holdings of camellias (hundreds of cultivars, in flower from November to April), cycads, tree ferns, hostas and Azorean endemic flora.
The thermal pool is the part most visitors come for. The water is held at around 35–40°C, has a brown-orange cast from dissolved iron, and is genuinely warm enough to wade about in even on a cool day. The iron staining is permanent on light-coloured swimwear, so bring dark trunks. Entry costs around eight euros (2024) and includes access to the pool; the garden is open from 10 to 18 in summer, slightly shorter in winter. Allow two to three hours.