Complex sentence: The Battle of Okinawa, the only ground engagement of the Pacific War fought on Japanese soil, claimed over 240,000 lives and destroyed buildings on the island along with countless historical documents, artifacts and cultural treasures.
Split into simpler sentences: The Battle of Okinawa was the only ground engagement of the Pacific War fought on Japanese soil. Over 240,000 lives were lost and numerous buildings on the island were destroyed along with countless historical documents, artifacts and cultural treasures.