Scrovegni Chapel

Definitely book the ticket with time window in advance and be there on time.
Admission is limited to 30 minutes, the first 15 minutes the pictures are explained in an air-conditioned room, after which you have 15 minutes for the chapel.

The Cappella degli Scrovegni: this famous chapel is a gem.
Giotto painted 39 frescoes about the lives of the Blessed Virgin and Christ (between 1305 and 1310). The virtues (right side) and the vices (left side) are depicted at the bottom. At the back of the facade you see the last judgment and there is one at the front
Madonna by Giovanni Pisano. You can visit the chapel every day from 9 a.m. to 7 p.m. in groups of maximum 25 people. You can stay in the chapel for a maximum of 15 minutes.

It is recommended to book days in advance as it is often sold out, especially if you plan to go during the holidays or the weekend.