Traditional Batak houses with soaring roofs at Samosir Island, Lake Toba, with the ancient Batu Parsidangan stones in the foreground

samosir lake toba batak traditional architecture cultural heritage indonesia sumatra toba batu parsidangan tribal ancient meeting place trial stones iconic roofs alang houses tourism history ancestral landmark village wooden structure indonesian culture unique design travel destination historic site outdoor daytime no people tradition craftsmanship heritage preserved scenic attraction authenticity cultural identity roots sumatran indigenous structure architectural detail cultural tranquil ethnic conservation