By Becky Anderson, CNN
Pope Benedict XVI gave his final public address Wednesday before hundreds of thousands of people in Saint Peter's square.
His resignation takes effect Thursday.
The end of his papacy marks the beginning of a period of transition to his successor, which will be chosen in a papal conclave.
St. Peters square in the state of Vatican City is the spiritual and governing seat of the Roman Catholic church.
It is here that tens of thousands of pilgrims gather to await the election of a new pope, and it's here in the Vatican's Sistine Chapel that the new pontiff is chosen.
The vote will happen in the Sistine Chapel, which was designed to be the papal chapel.
It's one of the world's most famous galleries of biblical art, and it's here that the conclave of cardinals is held.
One hundred fifteen cardinals from across the globe are expected to gather to invoke the Holy Spirit for assistance before electing a pope by secret ballot.
On the first day of conclave, eligible cardinals may hold a vote. If there is no result, on subsequent days, they'll vote twice in the morning and twice in the afternoon until someone receives a vote of two-thirds plus one.
Since the cardinals meet in isolation, the only way the public knows about proceedings is through one of the most famous traditions of the papal succession ritual.
The appearance of smoke from the chimney over the conclave room indicates a vote has taken place.
The ballots are burned after each vote, with black smoke from that chimney indicating a failed ballot and white smoke meaning a new pope has been elected.
Shortly after the decision has been signaled, the new pope will appear in front of a throng of onlookers and give his first apostolic blessing from the window over St. Peters Square.