Vatican Necropolis Temple Under St Peters Basilica

The Vatican Necropolis lies under the Vatican City, at depths varying between 5–12 metres below Saint Peter's Basilica.
The Vatican sponsored archaeological excavations (also known by their Italian name scavi) under Saint Peter's in the years 1940–1949 which revealed parts of a necropolis dating to Imperial times.
The Vatican Necropolis is not to be confused with the Vatican Grottoes, the latter of which resulted from the construction of St. Peter's Church and is located on the ground level of the old Constantinian basilica.

An ancient Roman necropolis, or city of the dead, is now open to the public in the Vatican City.
https://mymodernmet.com/via-triumphalis-necropolis/
https://www.youtube.com/watch?v=Z-fP9C5Fo8A&t=13s

St Peter's Tomb: How To See One Of The Most Exclusive Vatican Sites.
https://www.youtube.com/watch?v=g5Bjen8g4Gc&t=0s

Vatican Secret Archives: The History of Humanity Locked Away :
https://www.youtube.com/watch?v=cfuEdaw283I&t=8s

The Lateran Apostolic Palace opens for public to view Pontiffs' private rooms:
https://www.youtube.com/watch?v=DOD_9DINdX0

Palatine palace also known as The Domus Tiberiana or the House of Tiberius was the first true imperial palace on the Palatine
The Domus Tiberiana: Palace of Tiberius:
https://www.youtube.com/watch?v=M2U1jLYNdrI&t=9s