Halemaumau is the crater within the caldera. It's floor is measured at 3,412 feet above sea level, whereas the floor of the rest of the Kilauea caldera is higher at approximately 3,640 (the rim near the Volcano House is 3,980)

This crater last had some activity in 1974. It is a spectacular feature of the caldera, and with it's contrasting white walls, it looks like a moon crater reminding you that you are some place special.

Notice the splotch of yellow on the wall evidencing a sulphur flow.

During the period 1832 to 1923, a lava lake was almost constantly in motion within the crater pit.
The 1924 eruption put an end to that exciting era.

It is astounding to me that during these periods of activity, people still hiked to the floor of the caldera and near the edge of this fire pit to witness the spectacle. I doubt it would be allowed today.

This is the best picture my camera could make of the floor of the crater.

The hundred year period during which this pit was a constant lava lake came to an abrupt conclusion in 1924 when Halema'uma'u exploded!

The floor had fallen and subsequent steam from seeping water was the culprit.

With the blast the crater diameter increased from 1/4 to 1/2 mile with absolutely no regard for my camera lens.

As you see the look of the crater is drastically different from what it used to be.

It was like gazing at the sun at noonday, except that the glare was not quite so white. At unequal distances all around the shores of the lake were nearly white-hot chimneys or hollow drums of lava, four or five feet high, and up through them were bursting gorgeous sprays of lava gouts and gem spangles, some white, some red, and some golden - a ceaseless bombardment, and one that fascinated the eye with its unapproachable splendor.

Mark Twain 1866

By now I had hiked the entire distance around the crater in a clockwise direction and still the glance back had not failed to impress me to the point that I was inspired to remove my camera from its case and go through the entire initiation and settings procedure in order to capture this lovely picture for you. (I have a digital camera.)

Heretofore my entire experience on the mountain had been to the east and south. By making this simple circuitous route to the (ahem) official northern observatory site, sitting on the highest wall ot the caldera, I was well rewarded with an overview and different perspective of the whole affair.