Kauai's Waimea Canyon was rated the third best free attraction in the United States by travel Web site TripAdvisor.

No. 1 was the Bellagio Fountains in Las Vegas, followed by Arlington National Cemetery.

"As travelers look for ways to save on their vacation this summer, TripAdvisor has recommended top attractions with a price that appeals to even the most frugal visitors," said Michele Perry, vice president of global communications for TripAdvisor.