The first female Doctor of the Church, Teresa of Ávila, was a visionary who took matters of reform into her own hands. Even when the church authorities came against her, she stood her ground and held fast to her convictions. In so doing, she managed to persuade the Catholic powers to come around to her point of view. Teresa was not someone who took “no” for an answer; she charted her own course in life.

Although he was born in what was considered the backwaters of the Roman Empire, Saint Augustine of Hippo has long been renowned for his early religious and philosophical thought. He has been called a doctor of the Church for his unrivaled ability of patching up even the most complex of theological questions. He tackled such things as the condition of the soul and the omnipotence of God. During the course of his tenure as bishop of the North-African city of Hippo, Augustine often gained as many critics as he did followers.

Nikola Tesla was a major figure in the world in which he lived. As the 19th century gave way to the 20th, it was Tesla who would contribute to some of the world's most amazing inventions. It was Tesla's theories, patents, and experiments that would pave the way for the digital, wireless world we are so familiar with today. Tesla didn't enjoy the high honors bestowed on so many of his contemporaries, yet he enjoyed the power of knowing that it was his inventions that were powering the world, literally.

While names like Nero, Caligula, Hadrian, and Constantine grab all the attention with their exploits, Marcus Aurelius tends to sit more in the historical background of the Roman Empire. In many ways, he is a lesser known emperor even though his written works have stood the test of time. Marcus, a prolific writer and formidable scholar, was perhaps the first to fulfill Plato’s dream of the philosopher king.

Constantine the Great was one of the most pivotal figures in the history of the Roman Empire and the widespread expansion of the Christian religion. This is in no way an understatement; Constantine was not only one of the last truly powerful Roman emperors, but he also successfully reconstituted the whole empire according to his vision of Rome’s future. He played the most significant role in transforming the Empire from a Greco-Roman pagan dominion into a bulwark of the Christian faith, granting for the first time real temporal power for the early Christian church.

The Great Depression was one of the most trying eras in American history. All aspects of the US were affected. After the stock market crash of 1929, the nation was thrust into a decade of turmoil and change - in government, the economy, and culture. Many of the changes brought about by the Great Depression remain today.

In the midst of World War I, the Easter Rising took place in Dublin and throughout Ireland in April 1916. The revolutionary movement faced many problems from the beginning, including splintered leadership, disorganized support, opposition from moderate supporters of home rule, and prepared retaliation from the British.

Many ancient civilizations are described as mysterious, but none provide as many puzzles and unanswered questions as the Olmecs. These people arrived in lands near the Gulf of Mexico around 1500 BCE and brought with them entirely new concepts in terms of engineering, agriculture, and religion. The problem is we have no idea where they came from or how they developed these new ideas.

In the face of ruthless totalitarian rule, it is only the rare few who stand up at risk of their own life to do what is right. Dietrich Bonhoeffer was one of those exceptional individuals. Even on pain of death, he would not bend, he would not budge - this German pastor fought the Nazi regime with every fiber of his being.

Rosalind Franklin was what can only be called an overlooked genius. Although she was not fully credited for the feat at the time, her work led to major breakthroughs in our understanding of DNA. In fact, she took the first X-ray photo of DNA in all of its double helix glory. By the time her former colleagues were being showered with accolades for results they made at least partially based on her findings, Franklin would not be around to see it. Sadly, it’s believed that her use of X-ray equipment gave her terminal cancer, cutting her life short at age 37.

During the bitter winter of 1692/93, a group of young Puritan women in the colonial town of Salem, Massachusetts, accused more than 200 of their neighbors and fellow townspeople of using witchcraft to injure and torment them. This was an incredibly serious allegation that led to sensational court proceedings and ended with the execution of 19 people.

According to history books, the Roman Empire ended in 476 CE with the fall of Rome. But if you asked most people alive at that time, they would have pointed you to what they considered the continuation of the Roman Empire - the civilization we now call the Byzantine Empire. The Byzantines, however, were more than just a remnant of Roman glory. At its geographical peak, the Byzantine Empire stretched out across the Mediterranean world.

No historical figure’s life story offers a more intriguing and insightful look at a specific moment in French - and European - history than that of Joan of Arc. Over the course of a life that sadly lasted just 19 years, Joan of Arc completely altered the course of the Hundred Year’s War. Ultimately, Joan of Arc was burned at the stake for her insistence that she received counsel from God, but what she achieved as a result of this guidance is a truly incredible story.

What do you think of when you consider the Middle Ages? Knights in armor and damsels in distress? Vikings plundering monasteries? Religious dissenters burning at the stake? The dead bodies piling up as war, famine, and plague devastated Europe? Think again. While all these are part of the tapestry of the medieval era, the threads of politics, personality and war, culture, religion, education and the arts are vastly more intricate and fascinating.

The Crusades are the prototype and epitome of the Holy War. The fight to take control of the city of Jerusalem, believed to be the most sacred Holy City to two distinct religions of Christianity and Islam, has lasted far longer than the two centuries of the Crusades, and its reach has extended far further than Europe and the Middle East.