Today began underground.

Our first stop was the Lac Souterrain de Saint-Léonard, the largest navigable underground lake in Europe. If you’re planning a visit, reserve your tickets in advance. The boats have limited seating, tours often sell out, and with timed entry, there was virtually no waiting once we arrived.

The tour itself lasts about 30 minutes. We had dressed in layers after reading that the cave stays cool year-round, and we were glad we did. The contrast from the summer heat outside was immediate.

Our guide was just 17 years old and effortlessly conducted the tour in French, German, and English. What an impressive young man. Switzerland’s multilingual culture was on full display.

The underground lake stretches roughly 300 meters (about 1,000 feet) and was discovered in 1943 by Swiss speleologist Jean-Jacques Pittard. At the time, the water level was too high for boats to navigate the cave. Then, in 1946, an earthquake created cracks in the cave floor, lowering the water level just enough to allow small boats to pass. Sometimes nature rewrites the tourist guidebook.

Before leaving, we wandered through the gift shop, which was surprisingly charming and definitely worth a quick look.

From Saint-Léonard, it was just a 15-minute drive to Sion, a beautiful valley town watched over by two historic landmarks perched on neighboring hills.

On one hill stands Château de Tourbillon, a fortified castle built between 1297 and 1308 by the bishops of Sion. Originally constructed as both a military stronghold and the bishop’s residence, it commanded sweeping views of the Rhône Valley and served as a powerful symbol of the church’s authority. Although much of the castle was destroyed in a devastating fire in 1788, its stone ruins remain remarkably impressive, and ongoing restoration continues to preserve this piece of Swiss history.

Across the valley sits the Basilique de Valère, built between approximately 1100 and 1130. More fortress than church in appearance, the basilica served both religious and defensive purposes during the Middle Ages. It is home to one of the oldest playable pipe organs in the world, dating back to the 15th century, and has been an important pilgrimage site for centuries. Walking through its ancient stone walls, it’s impossible not to imagine the generations who climbed the same path long before us.

Amir was determined to tackle the climb to Tourbillon Castle despite the 90-degree heat and the altitude. The rest of us were a bit less ambitious. We settled into a café where the kids enjoyed ice cream while Lidia and I cooled off with Aperol Spritzes.

Eventually, Lidia and #1 Big Brother decided they wanted to join Amir after all. As Lidia wisely pointed out, she may never have another chance to visit this place. Opportunities like this aren’t meant to be watched from a café.

Meanwhile, the two girls and I finished our treats and opted for the gentler climb to Valère Basilica instead. With more shade and a slightly more forgiving ascent, it felt like the right choice for us.

As always, the climb proved worthwhile. Whether you conquer the castle or the basilica, the reward is the same: panoramic views of the valley, vineyards stretching into the distance, and the satisfaction of knowing you earned them. Everyone returned with huge smiles—and, of course, enough photos to prove their accomplishment.

On the drive home, we stopped at the grocery store to pick up dinner. One thing we’ve learned quickly is that Switzerland is breathtaking… and breathtakingly expensive. After paying 25 CHF (about $30) for each of two small plates of plain penne with tomato sauce for the kids at lunch, we unanimously decided tonight would be a home-cooked meal.

Amir fired up the outdoor grill, cooking two kinds of Swiss sausage, chicken satay, and a spread of delicious sides. We finished dinner with chocolate biscuits from the chocolate factory we’ll be touring before we leave—a little preview of what’s to come.

Tomorrow promises another adventure as we head to Mont Fort to ride one of the world’s longest and highest zip lines. At nearly 0.87 miles long and speeds approaching 60 mph, it should be equal parts breathtaking and terrifying.

I’ll let you know which one wins.

~Steph