What country or city ended slavery?

Answer 1

Hundreds of them did over history.

Here's just some examples:

• Persia, 6th century BC. Cyrus The Great abolishes slavery and introduces the first human rights
• India, 3rd century BC. Ashoka abolishes the slave trade
• Venice, 960. Pietro IV Candiano passed a law making slavery illegal
• London, 1102. Slavery deemed illegal (only in London, not the rest of England)
• Iceland 1117. Slavery deemed illegal
• Japan 1200. Slavery deemed illegal, but was acceptable to enslave prisoners and prisoners of war
• Kocula (Croatia), 1214. Slavery deemed illegal
• England, 1215. Magna Carta law makes slavery illegal
• Norway, 1274. Slavery banned
• France, 1315. King Louis X declares that any slave is automatically free the moment they step foot in France
• Sweden and Finland, 1335. Slavery deemed illegal
• Vatican, 1435. Pope Eugene IV declares slavery illegal for the church
• Vatican and Catholic countries, 1537. Pope Paul III forbids the slavery of newly-discovered races and tribes
• Polish-Lithuanian Commonwealth, 1588. Slavery deemed illegal
• Portugal, 1595. Chinese slaves banned (only the Chinese slaves)
• Japan, 1590. Slavery completely illegal
• Chile, 1683 (Spanish-owned). Slavery deemed illegal
• England, 1701. High courts declare that any slave who sets foot in England is automatically free
• Russia, 1723. Abolishes slavery but keeps serfdom
• Portugal and some of the Portuguese Empire, 1721. Slavery deemed illegal
• Massachusetts USA, 1783. Slavery illegal in this state
• New Hampshire USA, 1783. Slavery banned in this state
• Conneticut & Rhode Island, 1784. Slavery banned in these states
• Great Britain creates a new country, Sierra Leone, in 1787, as a free colony for emancipated slaves
• French colonies, 1794. Slavery illegal in all French colonies, not just mainland France, except Haiti (undone by Napoleon later)
• New Jersey USA, 1804. Slavery banned in this state
• Haiti revolts and gains independence from France, banning slavery in the process (1804)
• British Empire, 1807. Transporting slaves through British-owned land becomes a criminal offence for any visitors (and British mercenaries transporting slaves for other countries)
• Also in 1807, the British Royal Navy patrols the African coasts to stop, turn back or sink any slaving ships
• United States, 1808. Importation of slaves illegal (this law was part-forced upon them by the fact that the British Empire was making it extremely difficult for other countries to capture or transport slaves)
• British Empire in 1811 toughens laws against slavery, meaning even wealthy politicians from other countries with slaves can be arrested on British Empire soil

- By now, because the British Empire owned an incredibly large chunk of the world and patrolled the waters with it's powerfully advanced navy, slavery was becoming very difficult to practice. Many countries were forced to ban slavery from this moment on, purely because the British made slavery extremely difficult -

• Spain abolishes slavery in 1811 for most of their colonies except the ones that can be accessed easily (ie - where oceans were not patrolled by the British Royal Navy)
• British Empire bribes Portuguese politicians to make slavery illegal in most Portuguese colonies in 1815
• British Empire bribes Spanish politicians to make slavery illegal in the colonies that were not included in the 1811 Spanish law
• British Empire forms a treaty with Netherlands, Spain and Portugal to fight slavery together in 1818 (using their navy and military)
• Shortly after the treaty, New York USA is forced to set a date to free all slaves due to low number of slave imports
• Uruguay declares independence from Brazil in 1825 and, with the help of the British Empire, makes slavery transports through their country illegal
• Sweden joins the anti-slave treaty between Britain, Netherlands, Spain and Portugal in 1827
• British Empire deems slavery illegal in all of the Empire in 1834 with the rule to "obey or be severely punished". British Empire soldiers ordered to arrest all slavers on sight or risk being executed for deserting their posts (some British Empire countries refused to obey the first abolition law)
• In 1835 France and Denmark join the British anti-slavery treaty
• British Empire founds the organisation "Anti-Slavery International" in 1839
• Venezuela gets annoyed with Americans using their country to transport slaves, so in 1840, joins the British Empire treaty against slavery, giving them the right to arrest or attack Americans with slaves
• In 1841, Russia, Prussia and Austria agree to help the British Empire suppress slavery (with navy and military)
• East India Company forced under British Empire control in 1843, meaning no more slave trading for them. All East India Company slave ships are destroyed
• Most of the South-American continent, in 1843, decide they have no choice but to join the British Empire treaty against slavery
• in 1845 the British Royal Navy build 36 new ships with newly advanced weaponry, used to patrol oceans and coasts for slave ships. The British now had the firepower to sink any ship within just a handful of minutes
• Tunisia is pressured to abolish slavery by Britain
• The Ottoman Empire in 1847 abolishes slavery in their African colonies, purely because the British Royal Navy made it impossible to run a slave trade in Africa
• Pennsylvania USA, 1847, slavery illegal in this state
• France in 1848 creates a new country called Gabon, for emancipated slaves (similar to Britain's emancipation colony earlier)
• Persian Gulf has no choice but to sign the British anti-slave treaty in 1849
• Cuba abolishes slavery in 1862 due to the threat of Britain the members of the anti-slavery treaty
• Abraham Lincoln in 1863 declares all slaves in confederate-controlled USA free and any slave who sets foot on confederate soil is automatically free
• In 1865 the USA abolishes slavery completely in all American states
• Puerto Rico feels the pressure of the British Royal Navy in 1873 and bans slavery
• Zanzibar becomes part of the British Empire in 1879, automatically making slavery illegal
• In 1921-1924, due to international anti-slavery pressure led by the British - Nepal, Morocco, Afghanistan and Iraq make slavery illegal
• Iran falls to pressure and makes slavery illegal in 1928, previously ignoring the British and their anti-slave allies
• The allies freed all slaves and war prisoners of Nazi Germany and Japan upon their defeat in World War 2
• The United Nations in 1948 declares that slavery is illegal world-wide. Not everyone listens to them
• Between 1952-1981, various Asian and Middle-Eastern countries ban slavery

So there you have it. Slavery has been ended by hundreds of countries all over history.

The main reason is because of the British Empire. They disagreed with slavery so much that they made tough laws against not only slavery, but transporting slavery through the British Empire.

They also developed a specialist navy just for stopping or sinking slave ships all over the globe, assisted by whichever countries agreed to sign the anti-slavery treaty with Britain.

Due to the military and navy pressure of the British Empire and its allies, the rest of the world slowly began to abolish slavery, just because Britain and her allies made it too difficult.

So, technically your answer would be Britain.

Answer 2

The first country to end slavery was USA. Abraham Lincoln was the first person to prohibit slavery.