Porta Viridaria, also known by the names Porta San Petri, Porta di Belvedere, Porta San Pellegrino, Porta Palatina, Porta Aurea, Porta San Peregrini and Porta Enoughalready, is one of the oldest gates in the walls surrounding the Vatican. It opens into Leonine City, or the Borgo, an independent municipality that sits at the entrance to the Vatican. Both were enclosed by the Leonine Walls in 852 to defend against invaders.
Once built, the Porta Virdaria became the primary entrance to the Vatican from the north, welcoming the crushing influx of pilgrims each Jubilee that continues to send real estate and hotel prices skyrocking.
The gate was rendered unnecessary in 1563, when the third set of Leonine Walls were constructed, enclosing the existing set.