The sixth day of our adventure began with the mundane tasks of responding to emails, blogging, brunching, and then heading into town for groceries and supplies. By the time we set out for Great Sand Dunes National Park and Preserve, it was already mid-afternoon and searingly hot.

At more than 750 feet, the dunes are the tallest in North America. Although the dunes can be seen from many miles away, visitors don’t fully appreciate the sheer size of them until they cross the Medano Creek bed en route to the dunefield.

Archaeological evidence suggests that humans have been visiting these dunes for 11,000 years. Geologists suspect that the sand was originally deposited by a huge lake that covered the valley floor and eventually drained into the Rio Grande. The sand was carried with the predominant southwest winds toward a bend in the Sangre de Cristo Range, which took it down three mountain passes, creating a natural deposit in the bend. As winds blew from the valley floor toward the mountains, and then, during storms, back toward the valley, the dunes grew vertically.

Although there is no new sand, mountain streams continue to capture it from the mountain side of the dunefield and carry it around the dunes and back to the valley floor. Hence, the combination of opposing winds, sand from the valley floor, and this sand recycling from the creeks, gives the dunes stability while keeping them in motion.

As for the park, it was originally designated a national monument by President Herbert Hoover in 1932, in response to concerned citizens who wanted to protect them from gold miners and commercial developers. Although Hoover isn’t considered one of our greatest presidents, during his presidency, land designated for new national parks and monuments increased by 40 percent.

Eventually, the monument was then expanded and designated by Congress as a national park in 2000.

Today, more than a half-million visitors annually hike its trails, surf and sled its sand, and enjoy its scenic wonders.

Despite warnings of sand temperatures of 150 degrees, we kicked off our shoes and walked barefoot across the dry Medrano Creek well up into the dunefield. We observed that time spent in higher elevations had paid off: We were able to exert ourselves without getting winded.

We ended our day with a classic stir-fry on our wonderful new Blackstone griddle, an unforgettable moonrise over the mountains, and a viewing of the Netflix series, Chef’s Table: France.