Read the following text then answer the question:
During the Civil Rights Movement in the United States, numerous leaders emerged to advocate for equality and justice. One of the most influential figures was Martin Luther King Jr., who delivered a powerful speech that continues to resonate today. In his speech, King addressed the issue of racial discrimination and the need for freedom for all individuals. He emphasized the importance of nonviolent protests and the power of unity to bring about social change. By analyzing King's words, we can gain insights into his vision for a more inclusive and equal society.
Based on the passage, what is the main topic of Martin Luther King Jr.'s speech?