Rogner Bad Blumau

In the 1970s a drilling for oil at Blumau found hot water instead, and in the 1990s the site was developed as a spa to a design by Friedensreich Hundertwasser, opened in 1997 - the largest inhabited work he produced. The complex is built into the ground as a series of grass-roofed mounds so that it reads as landscape from a distance, with undulating walls, no straight lines or right angles anywhere he could avoid them, mismatched windows, gold onion domes, ceramic columns and bands of colour. The thermal water comes up hot and mineral-rich and feeds indoor and outdoor pools. It functions as a hotel and day spa rather than a monument, so seeing it means buying a ticket, and the architecture is genuinely inhabited rather than preserved.

What you actually see

• Grass-roofed mounds - the buildings sunk into the ground to read as hills.
• No straight lines - Hundertwasser's principle applied across the whole complex.
• Hot mineral water - the thermal source found by an oil drilling in the 1970s.
• Gold domes and colour bands - the decorative language across the buildings.

When to go

All year; winter for outdoor thermal bathing in the cold. A day.

Honest expectations

It is a commercial spa - entry is a day ticket and not cheap, and there is no way to look round without one. It gets busy at weekends and in school holidays. Swimwear rules vary by area.

Nearby

Riegersburg castle and the Styrian volcanic land are south.