A bolt of lightning makes a dramatic display in the Chisos Mountains, tucked into the "big bend" of the Rio Grande. The 801,000-acre (3,242-square kilometer) Big Bend National Park is complemented by Mexico's Santa Elena Canyon Protected Area, created in 1994.

(Text adapted from and photograph shot on assignment for, but not published in, "Tex-Mex," February 1996, National Geographic magazine)