I recently spent two glorious weeks on vacation in Iceland, enjoying some of the most spectacular natural scenery on the planet. Some of it reminded me that sometimes, you need exotic locations for games. And sometimes, the exotic locations are as dangerous as the assassins hunting you.
This is Dettifoss, the "mightiest waterfall in Europe." 330 feet wide, 150 foot drop, thousands of *tons* of water per second going over, it is . . . impressive.
Tourists generally go to the west side, where there is a paved road, a parking area within sight of the falls, and an easy hike to the water. The more adventurous, looking for the better view, will take the poorly maintained gravel road to the east side, park about a kilometer from even being able to see the falls, and hike in. The covert operative, up to no good, would certainly not be interested in the always crowded tourist side.
The terrain is rough, broken and unimproved. For the first kilometer, there's a rough foot path worn by many feet. That tapers out once there's a decent, if somewhat distant, view (with a makeshift viewing platform) of the waterfall itself. To reach the water's edge is another half kilometer over broken, uneven rocks, often over a foot in their smallest dimension. Merely walking runs the risk of a turned ankle, or a tumble that could break bones - or heads. And at the end, however, you are literally at the water's edge, with no fences, guard rails, or even warning signs. Were I to run an encounter at such a place (and I probably will, eventually), the following rules would apply:
Movement is one half normal, with no sprinting possible. Movement of more than 1 counts as an action (but no DEX check required), and that action must be the first one taken in a given turn or the character ends up prone automatically, taking 1/2D damage from the fall.
Any kind of physical confrontation - a fistfight, etc. - requires an action (with DEX check) to maintain one's footing. Failure means the character falls down. Critical failure means 1D injury. This action may be taken before or after the combat action.
Dragging someone to the edge of the falls is a contested STR action (assuming they are resisting), or a straight STR check (if they are not). This check takes place after the attacker makes a DEX check to keep his footing. The target must also make a DEX check (first) if he does not wish to be drug prone across the rocks (1/2D damage per turn). Under no circumstances would it be possible to drag someone, resisting or otherwise, more than 1 space per turn.
Also of note: there is little cover. There are a few rocks large enough to hide behind, but not many. Unless a character has made an effort to be near one, assume the nearest is 1D spaces away, and only provides cover for about a 90 degrees angle at any given time. There is high ground, back from the water, on both sides of the falls, that would provide a sniper an excellent view of the east side. Less so the west side, because of the high ridge just back from the water, but still a good view. Remember, the falls are 300 feet across, so range across is going to be at least medium or long.
If someone goes over the falls, it is a 150 drop onto invisible, jagged rocks, with a half million pounds of water coming down on top of them. Per second. The only hope of survival is to use a Bone.
Other possibilities would be a rough cut stairway down the face of the cliff, well hidden by the spray, leading to a Secret Lair. Hiding surveillance cameras would be trivially easy among all the boulders. Using hollow rocks to hide servo controlled machineguns is as easy as carving out a rock and putting a hinge on the top.