Hawaiʻi Volcanoes National Park is absolutely stunning (and safe, away from the closed area). It's like being on a different planet. If you haven't been to the Big Island and the park, you should add it to your bucket list.

Decades ago, my wife and I visited the Big Island during a fairly sedate eruption. We drove down Chain of Craters Road, got to see a tiny lava flow (talking like a couple feet of glowing honey), but were wanting more. In the distance, we could see a huge steam column where a lava stream was reaching the sea. We asked one of the ever-attendant Park Rangers if we could walk over there. He said no.

But then he said - we close at 5pm, and there are no gates. OK, we can take a hint.

We drove to Hilo and bought cheap tennis and flashlights, then scurried back down Chain of Craters after 6. As the sky darkened, we walked towards the steam column. The rocks beneath our feet showed incandescent glows deep in the cracks, and we started to smell burned rubber from our cheap tennis. Eventually, we came to the lava outfall.

We watched nearly an hour as a river of molten rock cascaded into the ocean. We used our water bottles on our shoe soles, turning back when we ran dry.

I now understand that we were stupid - apparently the park loses a few tourists to shelf collapse each year - but we lived, and the memory is a treasure. Thank you, Mr. Ranger.

And yes, it's like being on a different planet - like being on our own, maybe 4 billion years ago.

Haleakalā is like this as well. Don't just drive up the crater - hike through the thing. It's a ~12 mile hike. It's a remarkable experience because the landscape changes so frequently and dramatically from desert to tropical forest.

The only comp to this is like the transition in Max Max from the desert to the oasis.

Tourists that drive to the crater, take pictures, and drive down have no idea what they're missing.

Sadly there was an ongoing eruption when me and my SO visited the Big Island, so the entire park was closed. Was a bit bummed out, on the other hand people lost their homes so keeping it in perspective.

That said, I second visiting the Big Island and visit various sites. Driving less than an hour and going from barren volcanic landscapes to lush rainforests was something else, and watching the sunset from Mauna Kea was magical. And lots of great beaches, and most that weren't next to a resort had very few people.

While the island is big relative to the other Hawaiian islands, its small enough that you can drive around it in a day.

I'd recommend staying on the Kona side, which is the dry and somewhat barren side. The Hilo side has rainforests for a reason.

Definitely a place to visit if you can. I traveled there in 1983 just as it was starting to erupt and visited a lot of places that are now under lava rock! In a later visit we were walking out to see one of the "peep holes" where you can see the lava down below and the rocks started getting slippery, except they weren't slippery it was our shoe soles melting, oops.

As postal mentioned below, Haleakalā is fantastic for that.

Also, I recently visited Mt. Aso in southern Kyushu of Japan and it really felt like I was on Mars.

Went there a little over a year ago. The steam vents were active, but no eruptions. The exhibits are wonderful and the birdsong in the evening is amazing.

How would you compare it to Iceland regarding volcanoes and all? Thats what we Europeans have in our backyard and its a properly stunning and otherwordly experience.