Historic and natural sites across Pennsylvania

The diabase boulder field covers 2 hectares. The stones create different metallic sounds when visitors strike them with hammers.

The private residence integrates into the landscape through horizontal concrete planes extending over Bear Run creek with its 30-foot waterfall.

The garden spans 35 acres and contains multiple garden spaces with native and exotic plants, water gardens and art installations.

The underground fire in this former mining town has been burning since 1962 and led to the complete evacuation of its population.

A spiritual garden containing 80 stones and monuments built in Celtic tradition. The park features stone circles and a replica tower.

Eight connected waterfalls in private property with wooden walkways and observation platforms throughout the Pocono Mountains forest.

The mine extends 300 feet underground. Former miners guide visitors and explain coal extraction methods from the 19th century.

This street from 1703 contains 32 houses in Georgian and Federal architectural styles with original doors and windows.

A public art space showcasing mosaics, wall paintings, sculptures and metal objects across a 5,500 square foot property in the North Side neighborhood.

Research center and bird monitoring site spanning 2,200 acres with hiking trails where visitors observe migrating hawks and eagles.

The public park contains a creek, several historical stone structures and a network of hiking trails through dense mixed forest.

This concrete museum building constructed in 1916 displays a collection of 50,000 historical hand tools and household items from past centuries.

The retired anthracite mine features a horizontal tunnel extending 1500 feet into Mahanoy Mountain. An authentic steam train operates on a one-mile track.

The medical museum contains a collection of anatomical preparations, pathological specimens, skeletons, historical equipment and medical documents.

The cave system takes visitors by boat through underground limestone passages. The wildlife park features North American animal species.

The world's largest bicycle museum displays over 6000 models, including historical specimens and collectibles from different time periods.

The highest point in Pennsylvania features a stone tower, viewing platform and trails crossing through Forbes State Forest.

A prison opened in 1829 with a radial floor plan. The facility contains seven original cell blocks and offers guided tours.

The grain mill from 1812 still produces flour using historical machinery. The building contains a museum and local artisan shops.

The state park contains a lake for fishing and boating, 10 miles of marked hiking trails, and a restored 19th century water-powered mill.

A residential building shaped like a shoe with five floors and a height of 25 feet. Mahlon Haines built it in 1948 as marketing for his shoe company.

An archaeological site containing artifacts dating back 16,000 years. The location was discovered in 1973.

Mining settlement from 1854 with preserved original buildings and exhibitions about miners' life in the 19th century.

A settlement from 1793 for French nobility. The site contained 300 acres of land with more than 50 houses.

This 36-mile recreational path built on former railroad tracks crosses abandoned mining settlements and features industrial heritage structures.

A working history museum producing handmade tiles in a traditional manner.

The University of Pittsburgh's scientific facility conducts astronomical research and hosts regular guided tours with telescope observations for visitors.

Eighteenth century brick house containing period furniture, antique collections and regular informational events throughout the restored interior rooms.

National Historic Landmark since 1998, featuring graves of 19th century generals, politicians and industrial leaders.

This yellow steel bridge spans the Allegheny River connecting Downtown Pittsburgh to North Shore since 1926. The name honors the Pittsburgh-born artist.

This funicular railway with 71 percent grade operates since 1891 and transported people and vehicles during the major flood of 1936.

Site of the 1777-1778 winter encampment of the Continental Army during the American Revolutionary War.

The estate features Edo period architecture with tatami floors, sliding doors and a pond containing koi fish.

The building contains furniture, artworks and objects from 19th century railroad industry life.

Built in 1873, the tower measures 68 feet and displays original lighthouse keeper quarters.