The Greek government is concerned that archaeological treasures do not disappear and for this reason diving is only allowed with a qualified dive company that will oversee underwater locations and activities.
People are not allowed to dive alone for fear that they might steal archaeological treasures.
The cathedral's original architect is unknown, but Pierre de Montreuil (who was involved in the building of Sainte-Chapelle) was responsible for a large part of the 13th-century work.