Final answer:
The Arena Chapel interior is a one-room hall covered with a barrel vault, known for Giotto's frescoes.
Step-by-step explanation:
The structure of the Arena Chapel interior in Padua, Tuscany in 1305 is a one-room hall covered with a barrel vault. This chapel is famous for containing a series of frescoes by Giotto that tell the story of Mary and Christ on the long walls. Moreover, the chapel structure itself features a simplistic design unlike more elaborate churches of the period, without side aisles or rows of columns, which emphasizes the importance of the frescoes within.