Climbing High into A Nest :Creative Elevated Natural Play Structures

I am not sure what this is: a castle, a nest? But that makes it even more intriguing.

I love the giant cat tail forest and elevated nest!

I was recently turned onto KuKuK, a group of German designers that does wonderful play environment design. Their spaces make me want to work harder and push the envelope here in the US. They use a lot of wood logs, crazy wood nests, and netting tubes to keep kids from falling. Their work actually looks pretty safe while being extremely challenging and inviting! Unfortunately the website is in German, but like they say a photo is worth a thousand words.

Here is a different view of the same sight. It looks so organic it could have washed up on the shore all by self!
Beautiful giant swing

 From what I can gather from the website translation they are a group of artists, designers, and architects. Their work is obviously custom and their organization as a design build shop helps them carry the design intent through to construction.

You can climb through the ladder tube into the elevated nest then across the enclosed suspension bridge. I wonder how they attached this to the tree?