Cave Playground Tunnels by Entre Prises

For those of you that thought the Krabbelknoten was a bit claustrophobic, take a look at the spelunking simulators designed by the firm Entre Prises in conjunction with the British Caving Association (an interesting play design overlap, there!). 

photo by David Cooke

Their Speleo System replicates natural cave features in modular sections that can be interchanged and even rotated to provide a variety of challenges, with the goal of introducing people to the sport of caving and preparing them for below-ground exploration. 

They provide the 'Linear', the 'Arch', the 'Chamber', and of course, the 'Squeeze'!  As well as make full artificial caves and enormous climbing walls for cruise-ships and casinos; those adult reincarnations of the playground. 

[Found at the always-interesting home of architectural conjecture:  BLDGBLOG.]