A study of material recovered from shipwrecks provides a fascinating display of the interplay of temperature, marine growth and oxygen content on the corrosion of metals. Analysis of corrosion products can give information about the changes in site conditions, as corrosion mechanisms are sensitive to changes in chloride and sulfide ion activities. Access to metal artifacts which have been exposed to a marine environment for centuries may provide the only valid results for long-term exposure tests. -- AATA