They have been declared natural landmarks and placed under protection.

See if the bridges and lions can be declared historic landmarks.

The houses, no longer a private enclave, have since been declared historic landmarks.

The town fought its removal and had it declared a National Landmark.

Five more, including Brinkerhoff, have not been declared landmarks.

The study was declared a National Historic Landmark in 1968.

In 1989 the building was declared a National Historic Landmark.

The site was declared a National Historic Landmark on 1964-07-19.

The building was declared a National Historic Landmark in 1961.

The house was declared a National Historic Landmark in 1960.