Hello :sombrero:
Last week I made this interesting trip around this road near to Texas;
It's Nuevo Leon state route 20, located here in route;
https://goo.gl/maps/gXDeLgc1FtK2
This route it's pretty beautiful, offers great views of stunning mountains and canyons in the Sierra Madre region, there are lots of pine trees (even some sub polar), desert canyon landscape and somewhat green tropical at the bottom. Here I do share some pictures;
This area is near between Coahuila and Nuevo Leon state limit, this are it's over 10,000 feet high, the road will start desending from this point:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FtjEZrYg.jpg&hash=d867ca5d8e2ad8b0b970e7538c22728f4973b628)
The state limit signal;
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F0XRfhFR.jpg&hash=8616a3f97a1d39cdcfa64e44bd8492914adbfaa5)
Great views of huge mountains of over 12,000 feet!
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FUeogv6P.jpg&hash=b552ab58e6c5642e3e59dea00a88232251e19ac1)
Some really nasty and sharp curves ahead, some of 180° turn;
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FccpSbnI.jpg&hash=338b55ecc1cca7466ec6e7210863c0e79ec02bc1)
Even clouds hits the mountains at this height;
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FFFDXM3Y.jpg&hash=42960fd7636ac869391edeabe07180274d537fd4)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FXvsYJ0g.jpg&hash=1e7e97050ae9b9a71f1451d2e2604a536d3bdba4)
Surprigsly there a small desert segment in the canyon, then again from nowhere the forest;
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F7P62h9b.jpg&hash=cd69eaf12af33f7ef6f4fc2922c0f485377e3663)
Here the San Isidro canyon, and some 4x motor tourist traffic:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzuzoYd2.jpg&hash=adfa120943b02ad560e4ab90c885d45259a2028d)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FSZnVwvR.jpg&hash=5d27856ffadca70add5ca0e7e2276e0512650489)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FY9dJX0e.jpg&hash=8efc26fb129c9ecec93afadc634c0b7bfb1f88aa)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FtqWkjvz.jpg&hash=24c994945aa60b5cb8c900055aacb75ec415a674)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FZfXskCE.jpg&hash=b15507a0ff126dd71f7c182f0a6c3ec75d6de7ba)
At this point its one lane road, should be caution for the incoming traffic
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FZ4HL3SJ.jpg&hash=47526215ad9e55540570cd57d643b8d0d4d9e0a5)
The road narrows and edges the canyon river
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FaKLW7y0.jpg&hash=727d50c919f6722513393e86335a23159c550c8d)
This area is soo green, right before to the abism...
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FoBUIeAd.jpg&hash=0892a7ae71847dee9f01226b329286d83e88d495)
Which you can see the huge valley above and the road dramatically descend in a series of hairpin curves and steep grades;
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FPJqXBXn.jpg&hash=100a08e5260898372b062b4613b0f7242a3ec83f)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FfOEW9xB.jpg&hash=db9c0791ecc78a54b13b5ad73d8ebf3a08c3be11)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FpziYYtv.jpg&hash=eb2aa2ee2af1c45655be0bf34430a3d2005ba666)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkFpfB9n.jpg&hash=b204b661fbe579cf4f092876e7885c328c0ecb9a)
There is also many crosses and religius monolits around the route, where people have died before, mostly of brakes failure.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FMVTd9j8.jpg&hash=946ac576f124f4bbd62d25f3ae23e2f161d4cc7c)
And for last at the bottom a waterfall next to the road! what a surprise...
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FDehHL9Q.jpg&hash=8d43b53c99ff2709014c98b44a3a3b3479f7fd09)
Worth the visit doing this trip, it's just 3 hours south of Laredo, Tx
Cheers