Question: What is the building that was built by Pope Sixtus IV and where the Papal conclave occurs?

Context paragraphs:
Pope Innocent VIII: Pope Innocent VIII (Latin: "Innocentius VIII" ; 1432 – 25 July 1492), born Giovanni Battista Cybo (or Cibo), was Pope from 29 August 1484 to his death in 1492.  Born into a prominent Genoese family he entered the church and was made bishop in 1467 before being elevated to the rank of cardinal by Pope Sixtus IV.  He was elected Pope in 1484 as compromise candidate after a stormy conclave.

Papal conclave, 1294: The papal conclave of December 23–24, 1294 was convoked in Naples after the resignation of Pope Celestine V on 13 December 1294.  Celestine V had only months earlier restored the Constitution "Ubi periculum" of Pope Gregory X, which had been suspended by Pope Adrian V in July 1276.  From that time every papal election has been a papal conclave.  It is the first papal conclave held during the lifetime of the preceding pontiff, the second such occurrence taking place in 2013 following the resignation of Pope Benedict XVI.

Papal conclave, 1549–50: The papal conclave from November 29, 1549, to February 7, 1550, convened after the death of Pope Paul III and eventually elected Giovanni Del Monte to the papacy as Pope Julius III.  It was the second-longest papal conclave of the 16th century, and (at the time) the largest papal conclave in history in terms of the number of cardinal electors.  The cardinal electors (who at one point totalled fifty-one) were roughly divided between the factions of Henry II of France, Charles V, Holy Roman Emperor, and Alessandro Farnese, the cardinal-nephew of Paul III.

Papal conclave, October 1503: The papal conclave of October 1503 elected Giuliano della Rovere as Pope Julius II to succeed Pope Pius III.  The conclave took place during the Italian Wars barely a month after the papal conclave, September 1503, and none of the electors had travelled far enough from Rome to miss the conclave.  The number of participating cardinals was thirty-eight, the College of Cardinals having been reduced by the election of Piccolomini as Pius III, who did not elevate cardinals.  At a consistory on October 11, Pope Pius had proposed to make Cardinal d'Amboise's nephew a cardinal, as part of his effort to conciliate the French, but the response from the Cardinals was not enthusiastic.

Papal conclave, 1585: The Papal conclave, 21–24 April 1585 – papal conclave convoked after the death of Gregory XIII, elected Cardinal Felice Peretti Montalto, who under the name of Sixtus V became the 227th pope of the Roman Catholic Church.

Papal conclave, 1484: The papal conclave from August 26–29, 1484, elected Pope Innocent VIII after the death of Pope Sixtus IV.

Papal conclave, 1471: The papal conclave from August 6-9, 1471 elected Pope Sixtus IV following the death of Pope Paul II.  With the exception of the conclaves of the Western Schism, this conclave was the first since 1305 to feature a working, two-thirds majority of Italians within the College of Cardinals, in no small part because of the absence of six non-Italian cardinals.  This was in part due to the unexpectedness of the death of Paul II.

Sistine Chapel: The Sistine Chapel ( ; Latin: "Sacellum Sixtinum" ; Italian: "Cappella Sistina" ] ) is a chapel in the Apostolic Palace, the official residence of the Pope, in Vatican City.  Originally known as the "Cappella Magna", the chapel takes its name from Pope Sixtus IV, who restored it between 1477 and 1480.  Since that time, the chapel has served as a place of both religious and functionary papal activity.  Today it is the site of the Papal conclave, the process by which a new pope is selected.  The fame of the Sistine Chapel lies mainly in the frescos that decorate the interior, and most particularly the Sistine Chapel ceiling and "The Last Judgment" by Michelangelo.

Papal conclave, 1455: The papal conclave from April 4-8, 1455 elected Alfons Borja Pope Callixtus III following the death of Pope Nicholas V.  The conclave was the first in the Apostolic Palace, the site of all but five papal conclave thereafter.  The conclave was also the first to feature accessus voting (votes cast "in accessit"), derived from a practice of the Roman Senate, where a cardinal could change their vote after an unsuccessful scrutiny to any cardinal already receiving votes.

Della Rovere: The Della Rovere family (] ; literally "of the Oak Tree") is a noble family of Italy.  Coming from modest beginnings in Savona, Liguria, the family rose to prominence through nepotism and ambitious marriages arranged by two della Rovere popes, Francesco della Rovere, who ruled as Pope Sixtus IV (1471–1484) and his nephew Giuliano (Pope Julius II, 1503–1513).  Pope Sixtus IV built the Sistine Chapel, which is named for him.  The Basilica San Pietro in Vincoli in Rome is the family church of the della Rovere.

Supporting paragraphs: Della Rovere Sistine Chapel
Answer: Sistine Chapel