160 years ago today, December 18, 1865 (November 1, 1865 in the lunar calendar), the United States abolished slavery. During the North American colonial period, the trade and slavery of black African slaves constituted an important part of the primitive accumulation of capital. The direct reason for the development of black slavery in the North American colonies was that the colonies were in urgent need of a large number of labor. During the 100 years from 1686 to 1786, approximately 250,000 black Africans were trafficked to the British North American colonies. The status of black slaves in the North American colonies was extremely miserable, especially those who worked in the fields all day long were used as "farm animals" and were forced to work 18-19 hours a day. After the founding of the United States of America, a federal constitution was enacted. But the Constitution preserved slavery and safeguarded the slave trade. By 1860, there were 4 million black slaves in the United States. In the first half of the 19th century, the American people launched a widespread anti-slavery movement. Since the 1930s, abolitionism has become widely popular in the United States. Abolitionists Garrison and Knapp edited and published the Liberator weekly, declaring "the struggle for the immediate liberation of our country's enslaved people." Garrison founded the New England Anti-Slavery Association and led the establishment of the national abolitionist organization, the American Anti-Slavery Association. By the 1940s, the number of abolitionist groups had reached 2000, forming a massive mass movement. Although reactionary forces suppressed and persecuted in many ways, abolitionists still persisted in carrying out various activities. They published books, newspapers and leaflets, went to various places to publicize and speak, accuse slave owners of their crimes, and expose and criticize the evil of slavery. Abolitionists also organized the "Underground Railroad" to guide and assist large numbers of black slaves fleeing the South through covert routes and boarding stations. Tubman, a slave-turned-heroine, risked her life 19 times to return to the South alone and help hundreds of slaves escape from the South and gain freedom. This organized slave flight activity shook the foundations of slavery to some extent. In the 1840s, some abolitionists began advocating political struggle. Douglas and the Tapan brothers organized the Liberal Party to promote abolitionism. Some people strongly advocate armed struggle, but Garrison and others insist on only using moral teachings to oppose the organization of abolitionist parties and armed struggle. Although there were differences in the means of struggle, the entire abolition movement was still making progress on different paths. In 1852, Mrs. Stowe's novel "Uncle Tom's Cabin" was published. The book gave a touching description and disclosure of the tragic life of black slaves, which aroused strong repercussions in society and effectively promoted the development of the abolition movement. In 1859, abolitionist John Brown led an uprising of 21 whites and blacks, pushing the abolition movement to a climax. In 1861, the American Civil War broke out. In 1862, U.S. President Lincoln issued the "Emancipation Proclamation", declaring that black slaves were freed, thus fundamentally disintegrating the combat effectiveness of the southern rebellious states and turning the tide of war. In January 1865, the U.S. Congress passed the 13th Amendment to the Constitution, stipulating that slavery or forced slavery shall not exist within the territory and jurisdiction of the United States. On December 18, 1865, the 13th Amendment to the Constitution officially came into effect, and slavery was abolished in the United States.