A cheerful Icelander with a Toyota SUV with tires that seemed nearly as tall as me picked us up for our tour of the Golden Circle.

“My name is Arnthorr,” he said as he shook our hands heartily, his golden hair bobbing on his forehead, “But if you forget my name, just yell, ‘hey Icelander!'”

We liked him instantly.

Arnthorr swam in the 1988 Olympics for Iceland. Now he’s a physical education teacher, but his hobby is off-roading. So on school breaks, he’s a super-jeep tour guide — it’s what he likes to be out doing, anyway, he said as he droves us out of Reykjavik toward the Golden Circle route that seems to be Iceland’s hottest tourist attraction.

The Golden Circle is a collection of pure Icelandic geologic wonders one can see in a day on a loop drive out of the city. Our first stop was an overlook across the yawning gap between the North American and European plates in Thingvellir National Park.

“What’s between the plates?” one of my brothers asked Arnthorr as he gazed across the valley beneath the cliffs we stood on, which formed the edge of the North American Plate, and down to the Althing, the site of the first Icelandic parliament more than 1,000 years ago.

“I don’t know, just enough lava to stand on, I guess,” Arnthorr said. “Don’t jump up and down on it.”

My brothers figured he was kidding, but they still looked a little nervous.

We continued across the rift to the European plate and on to Gullfoss, the next major attraction along the Golden Circle. We could see Gullfoss’ spray rising above the rolling green plain before we arrived at the massive waterfall (and the hordes of tourists).

We broke out our rain jackets before heading down to the falls. I was snapping pictures on the wet rock that dips into the falls when I heard a woman in a distinctly American non-accent squeal valley-girl style:

“Oh my God, we’re from Denver!”

I turned to see my mom talking with a couple who wanted their picture taken. The woman’s legs were bare under her flowery, flouncy skirt and punctuated by impossibly impractical heels. I shivered in the waterfall’s spray at the thought of it.

“You’re from Longmont?” she said as she handed me their camera. “Oh my God,” — her voice rose, peaking at God — “it’s such a small world!”

Too small, I thought as she posed on her husband’s knee, kicked up one leg and threw her arm back. I took a couple of quick shots with the falls in the background and got back to my own shooting quickly to avoid a conversation straight out of an ’80s teen movie.

Next, Arnthorr drove us up to the icecap, which we could see from the upper parking lot at Gullfoss, and the pleasures of having a private tour were readily apparent. There are plenty of bus tours of the Golden Circle, but the buses don’t do what Arnthorr did. Arnthorr drove us down a gravel road, which quickly got rough, past some snowmobilers, past the end of the road and right onto the glacier.

Our jeep was equipped with its own air compressor, so we stopped at the end of the road so Arnthorr could check the snow conditions and adjust the tire pressure accordingly (we paused again to re-inflate the tires upon returning to the road). I doubt any of us had given much thought to the required tire pressure for the varied ground we were covering, but Arnthorr educated us. We learned that the best way to travel on the glacier at this time of year, if possible, is to deflate one’s tires to 3 psi; 5psi can be adequate, but 3 psi is really the best way to float on the snow.

However, if the conditions are not right, and your tires are no good, they will fall right off the wheels at three psi, he said.

“They’ll come off?” I said.

“Oh, yes,” he confirmed.

At this point we were on the flat snowfield at the foot of the glacier. I was sitting in the middle of the back seat, which meant I had nothing to hold onto but my seat belt and camera bag. The bumps were getting bigger. I held one hand against the ceiling of the truck to stabilize myself, but I was still getting tossed all over the back seat while my family roared in laughter at me and took pictures.

The path smoothed out once we started up the glacier proper. Arnthorr told us where it would be dangerous to drive the jeep or walk — to the left, to the right, up ahead. Pretty much everything around us was dangerous. When he parked on top of the glacier so we could get out and look around, we were afraid to move off the jeep’s tracks.

I’ve been to Alaska in the winter, but I’d still never seen so much white. I suppose I’ll have to travel to Greenland or Antarctica to see more. What’s more, the biggest Icelandic icecap is far to the west; we’ll see it in a few days, if the weather cooperates. Arnthorr had taken us onto the edge of one ice cap, where ahead we could only see white, and another icecap was visible in the distance, I think to our east. I can’t say for sure, because frankly, I was turned around most of the time we were there. I usually have a good sense of direction, but when it’s cloudy most of the day and the sun doesn’t really rise or set, you start to wonder how explorers made it to the North or South Pole.

After being thrown all over the back seat again, we stopped at the road to fill up the tires — three psi is not safe on the road — and Arnthorr took us to Geysir.

Geysir is the original geyser. It’s not the first ever, of course, it’s just the first one somebody named. So all those geysers at Yellowstone have Iceland to thank for that useful brand name.

But the name and the thing itself are as far as the similarities go, because Geysir is no Yellowstone. A little rope about a foot off the ground is all that separated the biggest geyser from the crowds. In America, this would be a lawsuit waiting to happen. In Europe, it’s too bad you were stupid enough to walk into uber-hot water.

My brother Matt was incredibly tempted by this freedom. He wanted to walk through it. He wanted to stick his finger in the water of a tiny gurgling offshoot of the main geysers. So help him, he wanted to interact with the Mid-Atlantic Rift, Mother Nature be damned.

He was getting on my nerves.

“Just. Stop. Don’t touch the water. Just — ” I rolled my eyes ” — cut it out.”

The big geyser was shooting water 30 feet or so into the air, so I went to take pictures of it. Mom came up behind me and said Matt had thrown a rock into the gurgling pool below.

He walked up, and I laid into him. Yes, I am 30, and he is 14. I am an adult. But right then, he was my little brother, and being the big sister and the oldest child, I was of course smarter than him and had to tell him exactly what he had done wrong in the way that only an older sibling can.

“Why did you throw a rock into the geyser? Don’t you know that clogs them? People throwing things into them? Then they don’t erupt anymore. They die.”

Mom gave me a look.

“You think I’m kidding? They have signs all over Yellowstone, examples of clogged geysers, because people threw things into them.” (I haven’t been to Yellowstone since I was 14, so I don’t know whether that’s still true.)

Matt was “whatever”-ing me, and a nearby American couple said to Mom:

“Brother and sister, right? We’d spot that anywhere. It’s universal.”

I was trying to keep my brother from being the ugly American, but I had turned into the ugly American instead. That’s okay, though, because by now we were all laughing about me giving poor Matt such a hard time over a stupid rock. (In my family, bad behavior is generally made fun of, thus embarrassing the person behaving badly into not doing it again.) Would a rock clog a geyser, anyway? I know coins and other man-made debris do at Yellowstone. But a rock?

On the way back to Reykjavik, Arnthorr took an off-road route through the geothermal area that supplies Reykjavik’s hot water. Steam seemed to be pouring out of pipes and random cracks in the rocks all around as I was jostled about the back seat again. It was odd to me that we could drive right through the city’s hot water supply structures on well-used jeep roads. Back home in Colorado, Boulder’s supposedly pristine water supply, a reservoir a few thousand feet above the city right between popular hiking areas, has a wide berth that is completely off limits even to hikers.

Arnthorr had talked to us all day about the concerns Icelanders had about the environment and especially global warming. But four-wheeling doesn’t seem to be an environmental concern. It’s as if they know firsthand that in Iceland, the forces of Mother Nature are far more powerful than any super jeep.

That night, we spent our last night in Reykjavik. Icelanders partied in the streets into the wee hours again, so my folks were glad to leave town the following morning. We struck out on the southern part of the ring road that circles the island and spent the night near a spectacular waterfall, Skogafoss. Dad was reading his guide book that night and gathered us in my room to read a special passage:

“The great geyser at Geysir first began spouting in the 14th century, blasting a jet of superheated water up to 80m into the air, but the spring became inactive in the 1960s, after being bunged up by rocks and dirt tossed in by tourists attempting to set the geyser off.”

I jumped up to perform my in-your-face dance, followed by the I-was-right dance. My family brings out the best in me.