Podarcis Sicula; also known as Ruin Lizards.
Noticeable for its vibrant green colouring, the Italian wall lizard is Italy's take on the many varieties of wall lizard found in Europe.
In hot weather you'll see wall lizards basking everywhere from open archaeological areas like Ostia Antica and the Forums to walls and pavements right in the centre of town—anywhere there's a patch of waste ground, ditch, grassy verge, or flower pot to call home. They particularly like the nooks, crannies, and basking places found in archaeological digs, however, which is perhaps what's earned them the secondary name of ruin lizards.
Growing up to around 20cm (including the tail), the Italian wall lizard is fast and thin, able to scurry quickly into a safe place when spotted. (Unlike the gecko, which is more likely to stay still, maybe in the hope you'll mistake it for a pebble.) For this reason, attempts to photograph it frequently result in pictures of blank walls, maybe with the blurry tip of a tail vanishing into a crack between stones.
They feed on insects, which they catch in their mouths and thrash from side to side before swallowing—apparently they're also capable of athletic jumps to catch passing flies and moths. In their turn, they provide food for Rome's large native population of stray and feral cats, who apparently don't know that these lizards are a European protected species.