|Location:||Covanera, Burgos. 90km south of Santander.|
|As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.
|NOV-1964||exploration of the first 100m 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||383m of sump 2 reached by G.E. Standard.|
|1989||G.E.Gaia advances to 650m.|
|SEP-2002||sump 2 extended to 1,950m and a depth of -60m by Jason Mallinson.|
|MAY-2004||sump 2 extended to 2,220m and a depth of -70m 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 700m sump. After a 300m swim, a cascade, and a short stream passage a second sump is reached. This second sump is known for 2,220m and a depth of -70m and is the longest sump in Spain.