400-year restoration of walls of Cadiz continues

For 400 years, city officials in Cadiz, Spain have been charged with the task of repairing and restoring the city's massive walls. The masonry walls, damaged in 1596 by the English, serve to keep out the ocean.

Redesign has taken place over the centuries, but modern engineers are now looking at the 17th century breakwater as a model for planned construction, this time using concrete rather than sandstone blocks.