This Jubilee started on the 8th of December, feast of the Immaculate Conception, with the traditional opening of the "Holy Door" of the Saint Peter's Basilica by the Pope; and will end on the 20th November 2016, feast of " Christ the King".
The Jubilee has not, however, been invented in Rome by the popes but has his roots in the Bible. Exactly in the Book of Leviticus that says that, every 50 years, all the slaves and all the prisoners would be freed, the debts forgiven and the land returned to their former owners. All this, in the name of mercy of God.
Anyway, even for who is not religious or not a Roman Catholic it is absolutely worth to visit the marvellous four most important roman basilicas.