My Grandmother Survived the Holocaust. Her Quiet, Gentle Strength Inspired My Entrepreneurial Journey. Leaving a plum job for the uncertainties of entrepreneurship didn't seem such a scary leap knowing what she overcame.

Six years ago, my 100-year-old grandmother passed away. A few months after I helped carry Grandma Mira's body to her grave, I made a decision to leave my cushy job in venture capital to launch my own startup. There were many reasons why I decided to become an entrepreneur. I saw the market opportunity. I was also inspired by my father and grandfather, who were both small-business owners.

But my decision also sprang from a realization that would be familiar to people who have suffered a personal loss, for whom the passing of a loved one leads to a profound understanding that life is short. That's what happened to me six years ago. Grandma Mira's death was a tipping point event that convinced me I needed to pursue the opportunity in front of me or I would regret it on my own deathbed.

Her passing capped an incredible journey -- a life of sacrifice and pain but also one of unrelenting hopefulness. She was one of the most influential people in my life. Grandma Mira was a Holocaust survivor.

I now feel the need to share her story after a major report pointed to a troubling trend: Many Americans today have little knowledge or are misinformed about the Holocaust. According to the survey, more than a third of millennials believe that two million or fewer Jews were killed in the Holocaust. The actual number is around six million.

Fewer than a million Jews swept up by the Nazis survived that nightmare more than 70 years ago. Mira (Jamner) Deutscher of Strilke, Poland, was one of them. She endured a time of cruelty and death but emerged from the experience a woman of quiet, gentle strength.

What perhaps was most noteworthy about the way I remember her growing up was this: Grandma Mira was the hardest-working, most disciplined person I've ever known. Despite all the hardships she faced in her life, she was almost always positive and happy.

My grandmother lost most of her family in the Holocaust. Her parents, grandparents, sister, brother-in-law and her three-year-old niece were gassed at the Belzec concentration camp. Three of her brothers were shot and dumped in a mass grave in the Radlowice Forest.

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Grandma Mira was forced to work in the Sambor Ghetto, where she sewed army uniforms for the Nazis. One day, she and others were rounded up and taken to a Gestapo headquarters jail the Nazis had set up on a compound that was previously a barn. After they were documented, the Nazis began to march them out of the jail. Having seen others getting shot on the way to the jail, she understood that they were about to be executed. She decided to escape.

As they were walking in line, she noticed an open window from which she could escape. When the guards weren't looking, she and a fellow detainee hid behind a support column. Once the guards and other prisoners were gone, they jumped through the window, off the second floor of the jail, landing on a pile of hay. They hid themselves from the Nazis by covering themselves with hay. When night fell, she and her companion made their way toward the fence and climbed over barbed wire to freedom.

Well, not exactly freedom.

This next part of my grandmother's story is still hard for me to imagine: To survive the Holocaust and the war, Grandma Mira lived underground -- literally.

For nearly two years, grandma lived in a secret hole dug beneath a barn owned by a Polish Christian family who agreed to help her, her husband (my grandfather) and her sister-in-law (my grand-aunt), with whom she got reunited after her escape. The hole was so small they could neither stand nor lie down. The three of them were able to climb out of their hiding place only a few times a year, usually during Christmas when it was certain the Nazis were not around.

When they finally were able to leave their miserable hiding place, my grandmother was emaciated and weak. She weighed just 70 pounds. Mice had eaten parts of her shoes. It took her months to regain her strength and be able to walk again without crutches.

Her life after the Holocaust continued to be defined by hardship and sacrifice. She moved to Israel, where she lost her husband a few years thereafter, leaving her alone to care for a daughter, my mother. Later, she and my mother moved to New York, where Grandma worked for years in various sewing sweatshops while caring for her daughter.

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Grandma Mira became an important part of my family, especially in my teen years when she moved in with us. I remember her as a devoted matriarch who was constantly on the move. She was always working, cooking for us, taking care of our needs. My mother remembers a time when she was a teenager, Grandma Mira went to work at the factory even when she was ill from pleurisy, which caused swelling in her lungs. She'd go to work with a bandage around her rib cage.

Life was hard in their early years in the United States. My grandmother was constantly struggling financially. She never amassed wealth for herself. Growing up, I don't remember her buying anything for herself. Grandma Mira also didn't care much for gifts. When I was older and would offer to buy a gift for her birthday, she always refused. "I have all I need," she would say. "All I want is to see you."

Yet, I don't remember her ever saying, "I'm tired." I rarely remember her losing her temper or getting frustrated. She was the strongest, hardest-working, most disciplined person I've ever known. I also remember her as a cheerful and buoyant woman, with an ebullient laugh.

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Despite the horrors she lived through and witnessed, I never heard her complain or become emotional or feel sorry for herself. In fact, she rarely talked about the war. When we watched films or documentaries about the Holocaust on TV, I never saw her get weepy-eyed. She never felt the need to talk about what we just watched, or to look back on the war.

I think about her a lot. I always reflect on the life of this strong woman who was tough as nails, who for two years lived in a hole in the ground that could very well have been her grave. Grandma Mira came out of the Holocaust battered, humiliated, emaciated but unembittered and unconquered.

Stories of the Holocaust often are tales of misery, tragedy and bitterness. That's not the story of Mira Deutscher. When I remember Grandma Mira, I recall her grit and inner strength, but also her positivity and love for life.