Not only registers and volumes, budles and file folders, files and boxes, but also single documents, are housed in the various protected storage areas of the Archivio Segreto Vaticano. Parchments are stored flat in special acid-free cardboard cases in large sliding drawers and kept in two special climate and humidity controlled storerooms. The most important documents of the Archives are indubitably the 81 parchments with gold seals and these are stored in a dedicated air-conditioned sector together with other extremely important items. These include the famous volume of the proceedings of the trial against Galileo Galilei, the «Privilegium Ottonianum» dated 962 and handwritten in gold script on a purple parchment, and the Liber Diurnus Romanorum Pontificum, the oldest formulary of the Papal Chancery dating to the 8th - 9th centuries. Paper documents are mostly stored in the Bunker and other storage areas.
Plans for the two storage vaults under the Cortile della Pigna of the Vatican Museums were drawn up during the papacy of Paul VI and the bunker was inaugurated by John Paul II on October 18th, 1980. It is a fire-proof, two-storey reinforced concrete structure with a storage capacity of 31,000 cubic metres. Its fixed and revolving shelving system runs 43,000 linear metres and is designed to optimize high density, rational storage and efficiency. New technology monitors security, climate and humidity and the bunker is also provided with a HVAC system, an emergency lighting system and a paging system.
In 1933 the two floors of the former Pinacoteca Vaticana located on the western side of the Cortile del Belvedere were transformed into the «Scaffali in Ferro» and were lined with 13,000 linear metres of iron shelving on the orders of Pius XI.
The so-called «Soffittoni», the rooms above the Gallery of Maps in the Vatican Museums, were set aside by Pope Pius XII as storerooms for the Vatican Secret Archives immediately after World War II.