Built in 1307, Giotto's Arena Chapel, aka Scorvegni Chapel, should not be missed when visiting the Veneto. In Padua, it is often overlooked, which can mean smaller crowds during certain times and seasons.
After a video in English and Italian explaining the history of the small unassuming chapel, you march through a vacuum that removes impurities on your clothes, which helps preserve the interior and colours of Giotto's masterpiece. Then you may enter 10 or so at a time to observe each detailed panel.
Some represent the miracles Jesus performed, but what you should notice is the intensity of the figures depicted upon the wall and a striking representation of Mary's parents in love and kissing. Another image to notice is the kiss of Judas—where he kisses Jesus before he is to betray him—and Mary Magdalene's face of agony as Jesus hangs from the cross.
Also pay attention to the entire wall that depicts The Last Judgement where Jesus is surrounded by apostles and below him are those who are chosen to be escorted to heaven, while to the left of the image are those being tortured in hell by blue monsters.
The man who commissioned the Chapel, Enrico Scorvegni, is depicted next to the cross presenting Giotto's Chapel, within his hands, to the Virgin Mary.
Photos are not allowed within the Chapel and this rule is enforced.
(this image is credited to http://padovacultura.padovanet.it/homepage-6.0/2010/12/scrovegni_chapel.html)