Hveragerði's greenhouses are a genuine curiosity — tomatoes, cucumbers, peppers, and flowers growing year-round at 64°N latitude, heated entirely by the geothermal energy rising from the ground beneath the town. The town has been a centre of Icelandic horticulture since the early twentieth century, when the first growers realised that the cheap heat underground could make growing vegetables in Iceland commercially viable.
Some greenhouses allow visits by arrangement, and the Iceland Academy of Agriculture (Landbúnaðarháskóli Íslands) has facilities in the town. The most accessible evidence of the greenhouse tradition is in the flower shops and vegetable stalls that sell local produce — the tomatoes and cucumbers grown here are noticeably better than the imported alternatives sold in Reykjavík supermarkets. If you are visiting in summer, the contrast between the warm, productive greenhouses and the wild geothermal landscape immediately behind them is worth considering.