Whenever people ask me: 'Why didn't you get up when the bus driver asked you?' I say it felt as though Harriet Tubman's hands were pushing me down on one shoulder and Sojourner Truth's hands were pushing me down on the other shoulder. I felt inspired by these women because my teacher taught us about them in so much detail.

That was the moment I wanted to use bitcoin: when I saw Harriet Tubman on a $20 bill. It's like, when you see all the slave movies, it's like, why you gotta keep reminding us about slavery? Why don't you put Michael Jordan on a $20 bill?

Harriet Washington, in 'Medical Apartheid: The Dark History of Medical Experimentation on Black Americans from Colonial Times to the Present,' documents the smallpox experiments Thomas Jefferson performed on his Monticello slaves. In fact, much of what we now think of as public health emerged from the slave system.

My office walls are covered with autographs of famous writers - it's what my children call my 'dead author wall.' I have signatures from Mark Twain, Earnest Hemingway, Jack London, Harriett Beecher Stowe, Pearl Buck, Charles Dickens, Rudyard Kipling, Alfred, Lord Tennyson, to name a few.

We had no more courage than Harriet Tubman or Marcus Garvey had in their times. We just had a more vulnerable enemy.

My office walls are covered with autographs of famous writers - it's what my children call my 'dead author wall.' I have signatures from Mark Twain Earnest Hemingway Jack London Harriett Beecher Stowe Pearl Buck Charles Dickens Rudyard Kipling Alfred Lord Tennyson to name a few.

We had no more courage than Harriet Tubman or Marcus Garvey had in their times. We just had a more vulnerable enemy.