Complex sentence: Another attraction at the park is the Oregon Caves Chateau, a six-story hotel built in a rustic style in 1934; it is a National Historic Landmark and is part of the Oregon Caves Historic District within the monument.
Split into simpler sentences: Another attraction at the park is the Oregon Caves Chateau, a six-story hotel built in a rustic style in 1934. It is a National Historic Landmark and is part of the Oregon Caves Historic District within the monument.