In the middle of the square rises the obelisk point of convergence of different roads. Roman imitation of the Egyptian obelisks, it dates back to the Imperial age, it came from the Gardens of Sallustio, but it was put here as element of link between the church and the stairway.
The hieroglyphs were carved in Rome imitating those of the obelisk of Piazza del Popolo. At the corner formed by the convergence of Sistina Street and Gregorian Street stands Palazzetto Zuccari, planned by Federico Zuccari and known with the appellative of "house of the monsters" because the windows on the sides are modelled on mouths of monsters. Here lived the queen of Poland Maria Sobiesky.
Proscenium to the church is the monumental stairway of the church Trinità dei Monti planned in 1726 by Francesco De Sanctis and realized completely in travertine marble. He chose as reference and for inspiration the number three, in honour of the church of the Trinity, De Sanctis created a flight of steps divided in three parts which unite and then converge immediately in two opposite directions in an alternation of convexity and concavity of the walls, of the staircases and of its squares.
Since1951 in April andMay a great exhibition of azaleas gives to the stairway a particular fascination.