Complex sentence: The Mortuary Chapel, built of timber in 1866, was left to deteriorate without any repairs and was finally demolished in 1969; based on recorded drawings of it, a replica chapel was built and serves as the visitor centre.
Split into simpler sentences: The Mortuary Chapel, built of timber in 1866, was left to deteriorate without any repairs and was finally demolished in 1969. Based on recorded drawings of it, a replica chapel was built and serves as the visitor centre.