IF ONLY GEOLOGY LESSONS were always like this. After driving 25 miles east of Reykjavík, capital of Iceland, we change into dry suits and flippers. Like fish out of water, we slap our way awkwardly along a path and then down a flight of metal steps. We pull on our facemasks, bite onto the mouthpieces of our snorkels and take the plunge into the narrow, deep fissure that divides Europe from North America.

Iceland is the ultimate classroom. Who knew geology could be so much fun? Snorkeling along the Silfra Fissure in Thingvellir National Park is just one of the experiences in this remarkable country that will forever transform children’s (and parents’) understanding of our planet.

A 40-minute guided snorkeling tour, costing $150 per person with all equipment provided, adds an incredible dimension to learning. The minimum age is 14 (there are also height and weight minimums), and all participants must be able swimmers.

The dry suit keeps you warm in the frigid water, though you can still feel the numbing cold on the exposed flesh of your face. Minor discomforts are a small price to pay for the magical sensation of floating in astonishingly clear glacial water above a chasm that descends 65 feet.

You don’t have to get wet to experience the continental divide. For long stretches the fissure is dry, and you can walk along it. With rugged cliffs rising on both sides, you are actually within the gap between the European and North American tectonic plates.

You can get a sense of the awesome natural forces shaping Iceland even within your hotel bathroom. When you turn on the hot water faucet, there’s an unmistakable whiff of rotten eggs. The sulfurous water comes directly from geothermal springs up to 6,000 feet underground.

(Never put your hand under a running hot faucet in Iceland — it’s often at scalding temperature.)

This island nation learned to harness the vast quantities of raw energy bubbling beneath its rugged surface. All of the country’s power needs are obtained from renewable sources. Geothermal water heats the houses, while hydropower and steam turbines provide electricity.

The waste water from the Svartsengi geothermal power station, 27 miles from Reykjavík, has become the country’s top tourist attraction, the famous Blue Lagoon. Take your swimming things and some conditioner to restore your hair in the shower afterward, and prepare for one of the most memorable experiences of your life.

Although it is open year-round, the Blue Lagoon is particularly impressive in winter. Brace yourself for the short walk from the changing rooms to the water’s edge, then savor the relief as you immerse yourself in bath-hot spring water. The white silica sludge on the bottom of the lagoon is said to have healing properties, and many bathers scoop it up and cover themselves with it. Children under 8 are required to wear provided, inflatable armbands.

Perhaps the most spectacular manifestation of Iceland’s geothermal activity is found close to the Hvita River, a 90-minute drive east of Reykjavík. Here, threaded through with footpaths, lies a complex of natural bubbling pools of mud, fumaroles and geysers. The most dependable geyser is Strokkur, which erupts every 6–10 minutes, sending a plume of boiling water up to 130 feet in the air. The nearby Great Geysir is much less predictable, erupting to more than 200 feet two or three times a day. As with the Blue Lagoon, the sensations are enhanced in winter, when clouds of steam magnify each eruption in the freezing air.

As you’d expect in such a rugged landscape, Iceland has an abundance of waterfalls. The greatest of them all, Gullfoss, is easily combined with a visit to the geysers. In winter the 100-foot waterfall is often partially frozen, which makes for haunting photography. But this is one attraction best experienced in summer, in full flow, when the falling water is thunderous, throwing up clouds of spray.

Summer also provides the best time to go whale-watching, departing on one of the regular tours out of Reykjavík’s old harbor. The viewing success rate is 90 percent in the warm months, with free repeat tour vouchers given if no whales are seen. Common species include humpback and minke whales and white-beaked dolphins. The average whale-watching voyage lasts around three hours.

Of all the island’s natural wonders, the most dominant are its many active volcanoes. They cast a shadow over life here. When a major eruption occurs, day can become night, lava flows threaten roads and communities and international flights are disrupted. There is no timetable; eruptions can occur at any time, though usually volcanologists can provide a few days’ warning.

Thrihnukagigur magma chamber © SERGEMI | DREAMSTIME.COM

The legacy of all this volcanic activity is Iceland itself. Violent eruptions made — and continue to alter — the island’s incredible landscape. For the ultimate Icelandic geological experience, what’s better than to go inside a volcano’s magma chamber?

This rare privilege is possible in the dormant Thrihnukagigur volcano, 30 minutes south of Reykjavík. The age minimum is 12, and a good head for heights is essential. In the course of the tour, visitors are lowered 400 feet by open elevator into the volcano’s crater; the careful descent takes six minutes. At the bottom, you gain a firsthand impression of the sheer size of the magma chamber and a vivid impression of the forces that drive a volcanic eruption.

Iceland Info to Go

International flights arrive at Keflavík International Airport (KEF), a former U.S. military World War II airbase, 31 miles southwest of Reykjavík. Book in advance online for the Airport Express shuttle bus to and from the city; the drive takes 35–45 minutes. Most domestic flights, and services to Greenland, operate out of Reykjavík Airport (RKV) close to downtown.

Where to Stay in Iceland

ION ADVENTURE HOTEL An hour’s drive east of Reykjavík, set within rugged landscape close to Thingvellir National Park, this futuristic hotel on stilts seems straight out of Star Wars. A great place to witness the northern lights. Nesjavellir, 801 Selfoss $$$$

EYJA GULDSMEDEN HOTEL This 65-room, eco-conscious hotel in downtown Reykjavík offers beautifully designed, bright-but-cozy rooms, many with views across the city to Mount Esja. Brautarholt 10, 105 Reykjavík $$$

FOSSHÓTEL REYKJAVÍK Large, family-friendly, 4-star hotel within a short walk of the city center offers great views from the upper floors. All properties in the Fosshótel chain adhere to the highest environmental standards. Þórunnartún 1, 105 Reykjavík $$$

Restaurants in Iceland

JAMIE’S ITALIAN Pizza and pasta are the staples of this restaurant, carrying the signature of British celebrity chef Jamie Oliver. The restaurant operates a policy to eliminate single-use plastic. Hótel Borg, Posthusstraeti 11, 101 Reykjavík $$$

THE LAUNDROMAT CAFÉ Enjoy the fun and quirky décor and simple wholesome food; a great place for a burger or sandwich. This being Iceland, fresh fish features on the menu, especially cod and salmon. Austurstraeti 9, 101 Reykjavík $$$

GLÓ Four outlets in Reykjavík offer healthy organic dishes, primarily vegetarian and vegan. There is usually at least one chicken dish on the daily menu to cater to meat-eaters. Laugavegur 20b, 101 Reykjavík (and other locations) $$$