i was specifically thinking of ravines , cliffs and gorges where access is provided by the park service ..... there is one right by my house they provide a path and stairs to the top of a cliff , a trail along the edge and a path down the other side ...... if they provide your family access to it and your 4 yr old falls off the cliff would they not be as responsible ? your 4 yr old would not have been able to get there without their stairs ? i can think of many national parks across the country who provide stuff like this , nearby parking lots , access trails maintained by the park service , and even wheel chair access to some places , places you would never get your kids without their help ............i have seen exactly how that gorilla was displayed , not hardly like throwing a mamba in a crowd ..... a fence , i'd guess 3 feet , bushes , and the bushes you couldn't walk through they are dense and hard , either you'd need to go over them or under them , then a small cement wall with a 20 foot drop on the other side .......Cliffs and ravines are naturally occurring things, not man-made constructs. Putting a bunch of potentially dangerous animals all in one place and then charging money for public viewing requires some degree of responsibility on the part of the facility. Should we just drop a black mamba in the middle of a crowd so they can all check it out, and assume that everyone knows to keep their distance? Should the crocs be kept in a normal park style pool because everyone knows not to wade into a croc pool, right? There is a difference between encountering a rattle snake on a hike in the wild, and a person putting a rattlesnake in your bed. I don't suggest we fence off every venomous snake on the planet, and if someone puts a venomous snake in my house, they are responsible for what happens.