The Ordination Hall (Ubosot) of Wat Arun is the most religiously significant building and a masterpiece of high-level Rattanakosin-era artistry. The structure sits on a raised base, surrounded by a cloister and decorated with Chinese stone figures and iconic giant statues at the entrance. Inside, it houses Phra Phuttha Thammisara Ratchalokethat Dilok, the principal Buddha image whose facial features King Rama II personally helped sculpt. Furthermore, the inner walls are adorned with exquisite murals detailing the life of Buddha and classical literature, reflecting the deep faith and meticulous skill of ancient craftsmen.