Welcome to the city of refuge. Hawaiians fleeing death sentences were allowed to live here if they could make it before the sentence was executed. That was until 1819, when Kamehameha II ended the practice. Now it's a national park with many interesting features.
Those ~500 year old lava walls are a few meters thick.
The Hawaiians built habitable structures on them, like this:
The ponds hold rainwater and salt spray from the ocean behind me.
You can tell they're brackish by the abundance of pickleweed...
Unfortunately, the pickleweed is Batis martima, a Californian that arrived recently and is invasive here.
Conservation efforts are underway.
That green shrub is Morinda citrifolia, a widely distributed tropical species.
It makes a fruit the Hawaiians call noni. Traditional/alternative medicine people value it highly; science is not so sure. Ripe fruit is putrid (think vomit + fart), and usually found on the ground.
This green shrub is naupaka (Scaevola taccada syn. S. sericea), another medicinal.
The flowers appear to be halved, giving rise to a legend that you can read about here.
There are a few miles of trails and other things to see.
Next door is Two Step, a popular snorkeling site named for the two natural rock steps you take in to the water. I snorkeled for little bit and saw big schools of yellow tang (and many other things besides). I should have bought fins when I bought my snorkel and mask (for $20, at Long's). I felt a little bit insecure without fins. When you come, please do not step on the coral. Don't step on the coral anywhere.
The house in the background is flying the Hawaiian flag upside-down. I will let you intuit what that means for yourself.