Blautopf

The Blautopf in Blaubeuren is a spring of almost unreal color: a funnel-shaped pool on the edge of the Swabian Alb that glows turquoise to deep blue, about 10 miles west of Ulm in Baden-Württemberg. It is the source of the Blau River, the entrance to a vast underwater cave system and the setting of a beloved German fairy tale. If you are exploring southern Germany, it is one of the most rewarding short stops in the region.

Why the water is so blue

The Blautopf is a karst spring. Rain soaks into the limestone plateau of the Swabian Alb, flows through underground channels and resurfaces here at an average rate of roughly 2,280 liters (600 gallons) per second. The pool is about 40 meters (130 feet) across and some 21 meters (69 feet) deep. Exceptionally clear water absorbs red light, so over several meters of depth mostly blue remains. The color is strongest on sunny days after a dry spell; heavy rain turns it murky.

Locals once joked that someone poured a barrel of ink into the spring every day. The poet Eduard Mörike made it famous with his tale of the "Beautiful Lau," a water nymph who had to learn to laugh again. The Blautopf is also a designated geopoint of the UNESCO Global Geopark Swabian Alb.

The hidden cave system

Behind the pool lies the Blauhöhle system. Its first stretch of about 1,200 meters is completely flooded, and in 2006 research divers discovered a huge dry chamber beyond it, nicknamed "Apokalypse." The caves are not open to visitors, and diving in the Blautopf has been banned since the 1980s except for authorized research and rescue teams. Swimming is not allowed either.

Renovation through 2028: what to expect

The whole Blautopf area has been under renovation since August 2024, with work scheduled to finish in December 2028. The spring itself remains open: two temporary bridges lead to the water's edge and onto the loop path north of the pool. As of October 2026, keep these points in mind:

• The water level below the spring basin has been temporarily lowered since mid-May 2026, which can change how the site looks.
• The historic hammer forge next to the spring is closed during construction, and its waterwheel has been removed for now.
• The temporary access is not wheelchair accessible.
• Expect fences and construction noise.

Admission is free. Plan 30 to 60 minutes for the spring, or half a day if you add the monastery and old town.

How to get to the Blautopf

By train: Regional trains run from Ulm to Blaubeuren in about 20 minutes. Ulm is well connected by Deutsche Bahn ICE services to Stuttgart and Munich. The station is about 1.5 kilometers from the town center, so expect a walk of around 20 minutes. Regional trains are covered by the Deutschlandticket.

By car: Blaubeuren lies on the B 28 west of Ulm, roughly an hour by car from Stuttgart Airport and about two hours from Munich. Parking on municipal lots is charged daily from 8 a.m. to 6 p.m.

Day trip ideas: Combine the Blautopf with Ulm, or with a drive across the Swabian Alb to Lichtenstein Castle.

Nearby

• Blaubeuren Abbey: the former Benedictine monastery right next to the spring, known for its late Gothic high altar
• urmu Prehistory Museum: finds from the Ice Age caves of the Swabian Jura, a UNESCO World Heritage Site
• Ulm Minster: the world's tallest church spire, about 20 minutes away

The Blaubeuren tourist office at Kirchplatz 10 has current information on the renovation.