We are in 1979.
Work is underway on the arrangement of the cellars of an ancient house in via Campo Marzio 48.
Suddenly, 20 feet below the street level and under half-a-foot of water, large travertine slabs appear on which, in horizontal and vertical bronze lists, the zodiac signs of Aries, Taurus, Leo and Virgo are reproduced.
Expert archaeologists are summoned, who eventually say they have no doubt: it is a section of the large sundial that extended in the area of Campo Marzio, between the current via della Lupa and piazza San Lorenzo in Lucina, where in the 15th century a part of the large sundial had been discovered.
It is, with no doubt, the large sundial made by the emperor Augustus in the 10th century b.C.
A work that measures 500 feet by 180.

There was a base of an obelisk centrally superimposed on it, which Augustus had brought from Egypt.
The obelisk had the function of a gnomon, that is, an "indicator arm", because on the top stood a sphere with a tip, reaching a height of one hundred Roman feet, which is today's 110 feet.

The shadow of the sphere projected on the dial indicated the time, day and month.
In addition, at sunset on September 23, on the day and time of Augustus' birth, the shadow fell on the Ara Pacis as a tribute to the emperor.

The solar clock, conceived by the mathematician Facundus Novius, remained in operation only about half a century, because, as Pliny writes, it collapsed due to an earthquake and the floods of the Tiber, which were depositing large layers of slime on the plates of the dial.

So , everything was lost?
No. First of all, the obelisk came to light in five pieces, and was recognized for the one used as a gnomon by the Augustan inscriptions engraved on the base, which recall the conquest of Egypt.

It was restored with the fragments of red granite from the Colonna Antonina, which had been discovered in small parts not recomposable as early as 1703, and between 1790 and 1792 it was erected in Piazza Montecitorio in front of the Palazzo dei Tribunali, now the Chamber of Deputies.

And then it was decided to reactivate its gnonomic function, superimposing a globe with lots of heraldic symbols of Pope Pius VII, and pierced so that a ray of sunshine conveyed to the ground could pass through it, indicating the time on special strips to be placed in the pavement of the square.
But those strips did not arrive, and the bells of Montecitorio continued to tell the time.

Only recently the gnonomic function of the obelisk has been restored.

On June 7, 1998, with the inauguration of the new layout of Piazza Montecitorio, twelve guide-flints were in fact planted on the steps in front of the building, and the obelisk began to mark the hour again.