The Old Hall (formerly the ordination hall) of Wat Sala Daeng is a historical landmark reflecting the long history of Saraburi. Its simple yet solemn traditional architectural style perfectly preserves its ancient charm. Inside, it houses Luang Pho Yai (Luang Pho Muang Haeng), a highly revered sacred Buddha image, surrounded by walls adorned with exquisite ancient Thai murals depicting valuable Buddhist stories. The interior atmosphere is peaceful and cool, with the breeze from the Pasak River flowing through the old wooden windows, enhancing meditation and providing devotees with a profound sense of spiritual serenity under the shadow of faith passed down for over a hundred years.