What is missing from this list: Aventine, Caelian, Esquiline, Palatine, Quirinal, Viminal and ... ?

Capitoline is the missing hill from the Seven Hills of Rome.

The Seven Hills of Rome, east of the river Tiber, form the geographical heart of Rome, within the walls of the city.

The seven hills are:

• Aventine Hill
• Caelian Hill
• Capitoline Hill
• Esquiline Hill
• Palatine Hill
• Quirinal Hill
• Viminal Hill

Tradition holds that Romulus founded the original city on the Palatine Hill on April 21st, 753 BCE, and that the seven hills were first occupied by small settlements that were not grouped nor recognized as a city called Rome. The seven hills' denizens began to participate in a series of religious games, which began to bond the groups. The city of Rome, thus, came into being as these separate settlements acted as a group, draining the marshy valleys between them and turning them into markets (fora in Latin). Later, in the early 4th century BCE, the Servian Walls were constructed to protect the seven hills.

Of the seven hills of current Rome, five (the Aventine, Caelian, Esquiline, Quirinal, and Viminal Hills) are populated with monuments, buildings, and parks. The Capitoline Hill now hosts Rome's city hall, and the Palatine Hill belongs to the main archaeological area.