- Collegiata di Santa Maria Assunta
Old Testament by Bartolo di Fredi (~1360). - Collegiata di Santa Maria Assunta
New Testament by Barna da Siena and/or Lippo Memmi (~1345). - Siena Cathedral
More interesting details on the ceiling of the Piccolomini Library. - Siena Cathedral
Ceiling of the Piccolomini Library, painted by Pinturicchio (1503). - Santa Maria Assunta
Madonna con Bambino e i Santi Agostino, Girolamo, Martino e Nicola by Matteo di Giovanni (1463). - Palazzo Vecchio
Officially, such decorations are called grotesque. - Palazzo Vecchio
Grotesque or not, I like them a lot.