“Within the greige brick facade are the bones, blood, teeth, ashes, hair, and personal belongings of the holiest members of the Christian church: the apostles, saints and martyrs. There are approximately 5,000 relics in total.” Remnants of the Cross, splinters from the table at the Last Supper, etc.
Unfortunately, the Holy Foreskin was stolen in 1983 from an Italian chapel. Not to worry - the Holy Umbilical Cord remains in good hands in the Vatican.
Given that relics are a form of money making showboating, it does not make sense to keep these artefacts out of sight in the Vatican - better to keep them spread out and drawing in the money.
I’ll be here all week. Try the veal, and don’t forget to tip your server.
But seriously, I’ve been to St. Anthony’s, and my sense was that most the relics are second (belonged to or touched the saint during their lifetime) or third degree (touched a first degree relic post mortem.) First degree relics are actual body parts of the saint, and the Vatican has the largest collection so they can consecrate new altars.