At the northern tip of Ka'anapali Beach, a finger of black rock that was once molten lava juts out to the ocean, where adventurers can enjoy cliff diving.

Black Rock, Maui

The water at Black Rock Beach may seem calm, but the currents are strong and incredibly deceptive, quickly catching unaware bathers and pulling them out into nearby ocean depths.

No lifeguards are on duty at this beach, and a native legend considers it a place where the spirits of the deceased leaped to be united with their forebearers.

Brennecke's Beach is a small stretch of sand that sometimes has water as calm as a bathtub, but often, the waves are savage, with no lifeguards on duty.

Brennecke's Beach, Kauai

Brennecke's can be unforgiving. The middle of the beach forms water funnels prone to rip currents that combine with strong surges, which can smash against lava rocks.

Also known as Banzai Pipeline, this spot has consistent barrels and is where globally renowned professional surfing competitions are hosted each winter.

'Ehukai Beach Park, Oahu

Although the waves are smaller in the summer, they still build irresistible momentum as they roll in over a jagged reef, making this a waterway that novices should avoid.

On the Kalalu Trail is a gorgeous section of sand, but the water is merciless, powerful, and churning, and no swimmer matches its force.

Hanakapiai Beach, Kauai

There is no reef barrier here, so the beach gets the brunt of swells that roll in, and the currents below the waves are strong enough to yank bodies far away from the shore.

Visitors flock to Hanauma Bay daily to snorkel and see coral and sealife in a relatively safe environment.

Hanauma Bay, Oahu

However, past the reef, water currents that aren't immediately evident have powerful rip tides, and, unfortunately, drownings are common for those who venture out.