A view of the Palazzo Vecchio in Florence. The Palazzo's foundations are the site of an archeological dig. (Fabrizio Giovannozzi/Associated Press)

The city of Florence in Italy is lifting the covers of an archeological dig under one of its most storied buildings, the Palazzo Vecchio, which was once the seat of local government.

Starting today, 50 people will be able to view the site. This will only be allowed on the first Sunday of every month.

Visitors enter through a side door of the Palazzo, where a copy of the statue of David sits in front. They enter a cavernous room, where there's a series of trenches, metres deep, and criss-crossed by wooden planks.

Archaeologists have spent the past few years unearthing the remains of an ancient Roman theatre — known as the Commune — discovering how the city evolved over 2,000 years.

"The Palazzo Vecchio has preserved all of the structures, whether Roman, medieval and even up to the renaissance, in its foundations," says archeologist Lorenzo Spezzi, who has been working at the site since 2004.

"Here you see all of the ages of the city, from its establishment to the renaissance. That's the wonderful thing about this area. You see, even from one room, the evolution of the city of Florence."

Spezzi says workers have unearthed what he calls the "burrella," or corridors of the original building, leading to the lower levels of audience stands where the rich and powerful sat to watch the proceedings of government.

"The important people or [nobility] of the city didn't pass through the commoners who sat up at the back. They had their own entrance to get into the places of honour."

Medieval street with building facades revealed

In another trench, there is a pile of broken pottery urns, which helped date the theatre — confirming that it was one of the first structures built, after the Romans founded the colony of Florentia during the first century B.C. And it functioned for the next 500 to 600 years.

Archeologists have also uncovered chunks of marble which once decorated the theatre.

"The theatre on its own is already quite a find. It's a beautiful piece of work. This is the marvel that is being revealed here," says Spezzio.

In one trench, workers have unearthed part of a medieval street, complete with a cesspit.

"This street, we've discovered from the archives was called Via di Bellanda," notes Spezzi.

"Almost all of the facades of the buildings, looking out over this street have been preserved."

The city has announced plans for a more permanent guided tour, after the dig is finished in a few months. The tour would include the archeological site, as well as visits to other parts of the Palazzo Vecchio.