The color of the Colosseum

A restoration of the Colosseum, currently underway, reveals frescos in a corridor that has been sealed off since the 3rd century. Unlike the moss-and-marble walls of today, the building interior, in its day, would have been a Technicolor extravaganza.

"We're used to thinking that during excavations, archaeological surprises are a risk for builders and for the city's development," Rome archaeological heritage superintendent Mariarosaria Barbera said. "But here is a beautiful archaeological surprise ... a monument that has been studied and known and appreciated across the world, yet still provides surprises."

Experts believe that only 1% of the monument's colorful frescoes still remain.