The American Southwest.
Yes it is an incised river canyon.
Basin
one major land form is the great sphinx.
canyons
no
yes it is. It was formed by the River Colorado wearing it down. it used to be a great plain. (A flat expanse of land.)
Drama.
yes
a canyon
Yes, there is limestone in the Grand Canyon. It is primarily found in the form of the Redwall Limestone layer, which is one of the prominent rock layers in the canyon.
Ursa Major, the Great Bear.