7 days · Monterrey + Coahuila desert
The anxious question first: yes, you can drive this, and no, the desert stretches are not a lawless void. What they are is empty. The real risk out here is running dry or losing signal 90 minutes from the nearest Pemex, not anything dramatic. Treat fuel and daylight as the two rules you never break and the rest of the loop takes care of itself.
Days 1–2: Monterrey
Monterrey is a working industrial city that happens to sit under some of the best mountains in the north. Give the first day to the Cerro de la Silla views and the food — cabrito, machaca, and carne asada done by people who take it personally. Day two, get up to Chipinque early while the air is cool, then swing out to the Grutas de García. The city driving is aggressive and fast; if you are not comfortable with it, use apps or taxis in the center and save your own wheels for the open road.
Days 3–4: Parras de la Fuente
Southwest through Saltillo, the landscape flattens and dries out fast. Parras is the soft landing of this trip — an oasis town built around springs, with Casa Madero, the oldest winery in the Americas, still pouring. Book the tasting ahead. Spend the second day doing very little: the spring-fed pools, a slow lunch, shade.
Days 5–7: Cuatro Ciénegas
The northern leg is the serious one. Four hours across open desert with long gaps between services, so leave with a full tank in the morning and download your maps offline. Cuatro Ciénegas rewards it: turquoise pozas and living stromatolites you will not see anywhere else. Stick to the marked, permitted pools — the ecosystem is fragile and heavily protected, and rangers enforce it.
What a friend who lives here would tell you: fill up in Monterrey and again in Parras, never let the needle drop past half in between, and be off the highway before dark. That is the whole game.