Here are a couple pictures of the final result, with the lookout tower, climbing walls and ramp, flagpole (top of the flagpole is 21' above the ground) and woodchips.
Check
out the pictures of the treehouse we just added!
There's also a 12' high climbing walls on 2 sides of the lookout tower
for the big kids (adults):
Here's a view from the back with the cargo ladder
& entrance to the lookout tower
And looking up the tower to the lookout spot on top 
And this is the evolution of it - from the Winter of 1998-99
with 1st addition (the bridge & second climbing tower).
And this is how it looked originally (Spring 1998):
back
treehouse