Less than a month ago, Sam Simon stood on the steps of the Japanese embassy in Los Angeles to help lead a rally for World Love for Dolphins Day. The animal activist, who passed away Sunday age 59, was energized and passionate, taking photos with the crowd and decrying Japan's annual dolphin hunts. He was doing what he loved, what he believed in, and all part of the grand adventure he planned for himself following his terminal cancer diagnosis in 2012.

"I don't believe in miracles," Simon said following the public reveal of his battle. "And I don't believe in 3-6 months [to live]. I think it's an adventure and we shall see what happens."

Over the next two and a half years, Simon made good use of living past his estimated time of departure, starting with his desire to give away the $100 million fortune he accrued as both a co-creator of "The Simpsons" and an Emmy-award winning producer and writer for dozens of other hit series.

"The sort of lifetime achievement stuff that I'm getting now is kind of like Tom Sawyer's funeral because they all know I'm sick," he told The Hollywood Reporter in 2013. "I am getting buildings named after me and awards and stuff. The truth is, I have more money than I'm interested in spending. Everyone in my family is taken care of. And I enjoy this."

In addition to the millions he donated to both Sea Shepherd and PETA (the organization named their Virginia headquarters after him), Simon also funded financial miracles for animals in need — such as purchasing an entire fur farm to save chinchillas, rescuing an injured race horse, transferring 17 abused bears to a sanctuary in Colorado and much, much more. He also made sure that his animal-saving Sam Simon Foundation and its related Feeding Families program (which donates more than 400 vegan meals each day to people in need) would carry on long after his passing.

"One of the things about animal rights, which is not the only thing that I care about in this world, is that your money can bring success," he told THR. "I see results. There is stuff happening, really good stuff, every week."

In announcing his passing, the Sam Simon Foundation vowed to continue the work he started, adding: "We take comfort in knowing how many greetings he is receiving across that Rainbow Bridge. We love you Sam!"

As word spread, social media lit up with tributes and love for Simon and the incredible work he did for all species.

“This is truly a devastating loss, for me and for Sea Shepherd and for the thousands of people and animals whose lives have been touched by Sam Simon. He will be remembered as a great friend and as an unwavering defender of animals,” said Sea Shepherd Founder, Captain Paul Watson.

In an in-depth tribute to Simon, PETA president Ingrid Newkirk urged people to honor his memory by performing some small kindness for animals.

“The world could learn all about kindness from Sam’s example, just the things he said, and I hope everyone who hears about him will do something kind and generous in his honor, even give your dog an extra hour in the park or eat one meal that does not involve animal suffering,” she said.

On Twitter, Simon's passing quickly became a top trending event, with many famous names chiming in to remember the giant.

On January 22, perhaps knowing his time was growing shorter, Simon posted a tweet that summed up his life since starting his "adventure" — a life that while difficult and painful, was also miraculous, joyful and one hell of a ride.

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Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Sam Simon's passing sparks outpouring of love and gratitude
Simpson's co-creator and philanthropist passed away Sunday at 59 after a lengthy battle with cancer.