Tucked into the foothills of the Khao Yai Mountains in northeast Nakhon Nayok province, Thailand's largest dam (2.6km long and 93m high) is an impressive site from down below and serves beautiful views from the top. On weekends a shuttle bus (8.30am to 5pm Saturdays, Sundays and holidays; 30B per person) crosses the dam, or you can rent a golf cart (per hour four/six seats 350/500B) and drive yourself. Walking over is not permitted.
On the lake, boat trips to waterfalls are available – in high water the falls can be seen from the boat; other times you need to walk, and the paths can be muddy. Down below the dam, many companies run gentle kayaking and rafting trips on Mae Nam Nakhon Nayok when water is released (generally Friday to Monday) and daily during the rainy season. There are also inner tubes available for short floats.