Complex sentence: The building, then valued at $10,000, burned to the ground as a total loss, which included a large number of new books and materials, along with a brand new piano, that had just been acquired for the upcoming school year.
Split into simpler sentences: The building, then valued at $10,000, burned to the ground as a total loss. It had contained a large number of new books and materials, along with a brand new piano, that had just been acquired for the upcoming school year.