The Science Corner

For more than 20 years, a fresco by the Italian artist Spinello Aretino (ca. 1330–1410) lay trapped in the confines of glue-slathered cloth. The glue had irreversibly hardened into a crosslinked mesh and refused to release the fresco.

Read more about it here: http://www.chemistry.org/portal/a/c/s/1/feature_tea.html?id=c373e90833a27c168f6a17245d830100