The colonnade of St. Peter's Square in Vatican City, designed by Gian Lorenzo Bernini in the 1660s, exemplifies the Baroque city planning ideals of large public spaces with views of important buildings. Indeed, visitors walking through the long boulevard leading up to St. Peter's Square can see St. Peters Basilica from the beginning of the boulevard, and the magnificent building looms ever larger as one approaches. In the Square itself, the colonnade functions as the welcoming arms of the Church embracing the visitor. Bernini designed the Square to broadcast the Lord's and the Church's greatness and authority while simultaneously welcoming the pilgrim into the Church as a valued member.
"To the left and right of the central obelisk on the square are circular marble plates which indicate the foci of the elliptical square. When you stand on either of these plates and look at the nearest colonnade, it will look as if there is only one row of columns instead of four. Bernini wasn't just a great sculptor and architect, he also knew his geometry!" (http://www.aviewoncities.com/rome/ piazzasanpietro.htm).
http://www.vatican.va/various/basiliche/san_pietro/vr_tour/index-en.html offers a 360 degree virtual tour of St. Peter's Square as well as different views inside St. Peter's Basilica. Although these resources cannot entirely capture the experience of being at St. Peter's, they help convey a glimpse of the emotional experience afforded by this brilliantly designed monument.
http://www.theblaze.com/stories/2014/04/20/christ-is-risen-massive-crowd-joins-pope-to-celebrate-easter-sunday-in-st-peters-square/ has pictures and a video clip showing what St. Peter's Square looks like filled with over 100,000 people on Easter, Christianity’s most joyous day.
Summary of helpful links: