  Crumpled thin sheets are complex fractal structures whose physical properties
are influenced by a hierarchy of ridges. In this Letter, we report experiments
that measure the stress-strain relation and show the coexistence of phases in
the stretching of crumpled surfaces. The pull stress showed a change from a
linear Hookean regime to a sublinear scaling with an exponent of $0.65 \pm
0.03$, which is identified with the Hurst exponent of the crumpled sheets. The
stress fluctuations are studied, the statistical distribution of force peaks is
analyzed and it is shown how the unpacking of crumpled sheets is guided by long
distance interactions.
