I’m a member of the Hurricane Club but that was in our own bed. Another couple we know had sex in their car during the same hurricane. (If you’re going to die, you might as well die happy.)
On a paved driveway.
In the middle of a cornfield.
In the eurotunnel under the English Channel.
Behind the lions in Trafalgar Square.
In a queue in a restaurant while waiting to pay. Their credit card machine had died and they were having to phone every transaction through. It was taking ages and we had other things planned for that time. So we got it on while waiting. The manager noticed and made us leave and never come back. So sex and a free meal!
In a Buddhist temple while on a weekend retreat. The monks chanting provided a nice rhythm.
… are you playing Three Truths And A Lie, or are you playing Three Lies And A Truth?
In the top of a corn crib.
My bad. We’d have chosen someplace more private had not her curfew been looming.
Eta: Although Curfew would be a fantastic name for a lovechild.
In the dressing room of a Banana Republic.
In a dirty back alley under the 7 train.
In a Jeep, while a cow chewed her cud watching nearby.
In a closet.
In a pool.
On a balcony overlooked by some apartments.
On a motel bathroom sink while friends were sleeping.
We’ve done all of those, except it wasn’t a Jeep. It was a pickup. But, I didn’t consider those all that strange, so I didn’t post them.
I guess our strangest would be driving along a lonely road in Wyoming with the teenagers asleep in the back seat.
Hey, it was the strangest for me.
And I don’t know you, do I? 
The foot of the bed.
I just thought it was interesting that you listed four places and I’ve done variations of all four. But, I’m somewhat of a redneck, so sex with a bovine audience isn’t all that unusual. It was a bit strange for my city-born-and-raised wife, though. She felt like they were staring at her.
When our house got robbed and I lost all my jewelry the thing I regretted most was my Mile High Club pin.
I think the second strangest was in one of the film booths (is that what they’re called?) in a porno store, We kept having to stop and put quarters in the slot.
On top of a large rock just outside the perimeter of Devil’s Garden Campground at Arches National Park. (at sunset)
In the bed of my boyfriend’s pick-up truck parked in his driveway on the side of his house.
While a cop, with lights a-flashin’, was writing a speeding ticket to some poor schlub he stopped on the street next to us.
Missouri.
In my bedroom, with the door open, while two friends were in the living room.
On the roof of a parking garage overlooking beautiful downtown Burbank.
On the front lawn of my apartment building.
Under a full moon in an old Spanish mission (national park).
At night in a hotel roofgarden while a wedding reception was going on a short distance away. I was wearing a long, full skirt. I don’t think the party even noticed us.
Oooh, I forgot one. Let’s see if Tully has done this too, and if so, I’ll think he’s one of my exes. 
In a busy movie theatre parking lot. I bet those patrons had no idea what was going on in that mini-van parked so close to the door.
And I agree, long skirts can be the bomb.