It's not just the uber-rich freezing their brains and bodies when they die. An HBO show visited a conference filled with everyday people excited to do it.

• The series finale of HBO's "How To with John Wilson" explored cryonics and the quest for immortality.
• The topic has drawn the attention of the ultra-wealthy in recent years.

HBO's idiosyncratic docuseries "How To with John Wilson" recently aired its final episode, exploring — rather fittingly for the ending of a show — the topic of cryopreservation, or freezing one's brain or body upon death. It's a subject, along with immortality and eternal youth, that many people seem to be occupied with, especially Silicon Valley's ultra-wealthy.

Each episode of "How To" is framed at the beginning as an explainer on a certain topic, like "How To Appreciate Wine," or "How To Throw Out your Batteries," then follows the titular filmmaker down unpredictable rabbit holes. In the series finale, titled "How To Track Your Package," Wilson goes down one such rabbit hole and ends up at the 50th anniversary party for a cryonics organization called Alcor, talking to various guests on why they've planned on being frozen after death, in hopes of being revived down the line.

But most interestingly, the episode highlights that plenty of non-wealthy, unassuming people are also interested in having their brain or body frozen in the hopes of one day cheating death. Some fantasize about a high-tech future; some seem to be in denial about death as an inevitability; some want to see what progress the world will make.

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That's not to say that the process isn't expensive: Alcor charges $80,000 for neurocryopreservation (freezing your head) and $200,000 for whole body cryopreservation, plus annual membership dues. The majority of Alcor members, according to the company's website, fund their cryopreservation by naming the company as the beneficiary of their life insurance policy.

It's well worth the watch, and you even get to see some of the cryonic tanks where the human remains are frozen and stored.

Insider has previously reported on Alcor competitor Cryonics Institute, a more affordable alternative that charges $28,000 for a body to be stored indefinitely.

The overall narrative of the HBO show's finale ultimately implies that trying to extend something beyond its natural limits, be it a TV show like "How To" or a person's lifetime, might not always be the healthiest course of action. Nor is there proof that the tech is or ever will be possible to revive someone from the dead. But that hasn't stopped people from trying to preserve their youth and escape death, especially those with plenty of money to burn.

Billionaire investor and PayPal cofounder Peter Thiel has plans to be cryogenically preserved when he dies, even though he openly doubts that the tech will ever work.

"I think of it more as an ideological statement," he once said in a podcast interview with writer Bari Weiss. "I don't necessarily expect it to work, but I think it's the sort of thing we're supposed to try to do."

He said in the same interview that humanity "should either conquer death or at least figure out why it's impossible."

OpenAI CEO Sam Altman has reportedly been interested in anti-aging methods for years. He told MIT Technology Review earlier this year that he's invested $180 million in a biotech startup called Retro Biosciences, which aims to delay death through the prevention of age-related diseases. The company's ultimate mission, according to its website, is to "increase the healthy human lifespan by ten years."

Jeff Bezos has also joined in on the immortality investments — he's invested in Altos Labs, a startup aiming to develop therapies to stop or reverse the human aging process, MIT Technology review previously reported.

Tech executive Bryan Johnson has also made waves for his anti-aging efforts. He reportedly spends $2 million a year trying to reduce his "biological age," taking 111 pills a day, eating all his food between 6 a.m. and 11 a.m., using a light therapy mask, and at one time receiving blood plasma infusions from his own teenaged son before stopping the practice because of lacking evidence it had any benefits. Johnson claims that he's reversed his epigenetic age by 5.1 years.