Original: Bernini 's first work at St. Peter 's was to design the baldacchino , a pavilion-like structure tall and claimed to be the largest piece of bronze in the world , which stands beneath the dome and above the altar .
Simplified: Baldacchino and niches Bernini 's first work at St. Peter 's was to design the '' baldacchino '' which is like a tent or '' pavilion '' above the High Altar .