The Retreat at Blue Lagoon Iceland by Basalt Architects and Design Group Italia is built directly into an 800-year-old lava flow. Located in the the heart of the Reykjanes UNESCO Global Geopark ...

Here among the towering basalt columns, the visitor stands inside a lava flow. Magma that swelled up from deep in the Earth cooled so gradually that it formed regular octagonal shapes as it shrunk.