Whilst in London I also visited the Rhizotron and Xstrata treetop walkway which was opened in 2008. It was designed by Mark Barfields architects who designed the London eye. The design is based on the Fibonacci numerical sequence. The word 'rhitzotron' is derived from the greek word 'rhiza' which means 'root'. This 18metre high 200metre walkway towers up from the ground supported by rusted steel colums. It was inspiring to be so high amongst the tree tops.