Imagine - a park that transports you back in time...to an alternate history where all of the Nazis of World War II had their arms replaced by chainsaws. Also, they're robots. Also, they all have rabies and are being kept in water-damaged cardboard boxes. Imagine the awe of paleorobonazitologists, witnessing living Nazis with chainsaws for arms for the first time after studying their robot-skeletons for so long.
Safety Measure: They're all female Nazi robots with chainsaws for arms, so they can't reproduce.
Imagine - a park that transports you back in time...to one of the darkest periods in human history: the time of the Bubonic Plague...except worse, somehow. Maybe, like, your dick gets real huge and then blows up or something. Enclosed in carefully-constructed cages are thousands upon thousands of rats infected with the worse-than-normal plague, which our captive guests will delight in viewing on their mandatory nude hike through the flea-infested jungle.
Safety Measure: The cages were built to hold a Tyrannosaurus Rex, so the bars are probably a little bit wider than they should be to hold in rats. But Muldoon, the rat wrangler who both fears and respects them, has assured me that there is nothing to worry about.
Imagine - a park filled with the most dangerous substance known to mankind: enriched uranium. Thrill-seekers from around the world will search out our park, filled with a danger that no one has ever known before. I'm sure our underpaid obese traitorous IT guy will be of no consequence.
Safety Measure: The sacks are tied with a double knot of twine
Imagine - a park that allows you to confront your actual nightmares in a physical space, thanks to science or magic or something. Yes, we've built a machine that makes all of your worst fears come true and we put it on an island off the coast of Costa Rica and think it would be a good idea to open this shit up to the public.
Safety Measure: The machine has a sign that says "DO NOT TOUCH"
Imagine - a park filled with eccentric billionaires who want to leave an impressive legacy behind by sparing no expense to build parks filled with scientific wonders. These billionaires will have an idiosyncratic sense of style and will blindly charge forward to test the limits of biology in the name of entertainment. They'll all have rockin' canes.
Safety Measure: They'll only make elaborate, expensive, scientifically-ambitious parks that they KNOW are totally safe, so don't worry.