Outside of the city you can find more interesting places
Grottos de García (like Caverns): they are at about 40 km. from the city of Monterrey, in the municipality of Garza García. You are arrive to them by a cable car and that travel the 16 rooms of underground formations.
Cascada cola de Caballo: is at about 36 km. from Monterrey in the National park of Monterrey. Presa de la Boca: near the same Cascada cola de Caballo is the dam 'Presa de la Boca', which is an ideal place to practice several aquatic sports, like fishing, ski, etc.
The Garcias´s Caverns are excelents, discovered in 1843. TIP: everybody know the regular track (2.5 Km), if you are lucky you may ask for the large track (about 3.5 Km) only thursday at middleday. Outside the cavern and before you star to climb, point yours eyes toward the mountain and you can see a blue eyes gorila, and an indian profile (imagination is required). Inside are 50 millions years marine fossils.
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Grutas de García (caves)
Go by bus and then take a taxi or hitchhike. An old rail car takes you up the mountain to the caves if you don´t want to walk.