Pozo Azul

Useful Information

Location: Covanera, Burgos. 90 km south of Santander.
Classification: SpeleologyKarst cave
Dimension: T=11 °C (water)
Guided tours:  
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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NOV-1964 exploration of the first 100 m by Joaquín Plana from G.E.Edelweiss.
1979 first sump crossed the first time by two divers from the G.E. Standard (STD) from Madrid.
1981 second sump reached after the exploration of the subaerial section.
1983 383 m of sump 2 reached by G.E. Standard.
1989 G.E.Gaia advances to 650 m.
SEP-2002 sump 2 extended to 1,950 m and a depth of -60 m by Jason Mallinson.
MAY-2004 sump 2 extended to 2,220 m and a depth of -70 m by Jason Mallinson.


Pozo Azul (Blue Pot) is a deep blue karst spring, as the name suggests. It is much visited by tourists. The cave behind the spring is filled with water and only accessible to cave divers.

The water of the spring emerges from a huge cave, starting with a 700 m sump. After a 300 m swim, a cascade, and a short stream passage a second sump is reached. This second sump is known for 2,220 m and a depth of -70 m and is the longest sump in Spain.