This is an Italian commemorative coin. It is dedicated to the 150th anniversary of Rome as the capital of Italy. 

It's funny that there was a person who thought that Rome was 150 years old :) 

What is depicted on the reverse. In the center we see the image of the goddess Roma (Rome). This image is taken from a statue from the Altar of the Fatherland (Altare della Patria) or Vittoriano (Il Vittoriano). 

A few words about this cultural monument. This is a memorial dedicated to the first king of the united Italy. It was erected on the anniversary of the unification of Italy. A huge building that is located in the center of Rome and includes a huge group of statues and elements. There are symbols of noble cities, there are symbols of the regions of Italy, there are symbols of pride and the idea of Italy. There are many symbols from mythology and geography. 

In the center of the Altar there is a statue of the goddess of Rum on a golden background. She is the central figure, and it is she who is depicted on the coin. 

Also on the left are two letters RI which translate as the Republic of Italy. Below there is the letter R - meaning Rome. There is an inscription on top: Roma capitale - the capital of Rome. 

The circulation of this coin is 3 million copies, the release date is 2021. 

Very often I see the value of a coin on ebay and other sites several hundred euros. Don't believe it, it costs about 3-4€ on specialized numismatists' websites.