Wikipedia:Selected anniversaries/December 18
- 218 BC - Hannibal had his first great victory over the Roman Republic at the Battle of the Trebia.
- 1352 - Innocent VI was elected Pope, succeeding Clement VI.
- 1865 - Slavery in the United States was abolished when the Thirteenth Amendment to the Constitution was adopted.
- 1961 - Indonesia invaded the Dutch East Indies to annex West Papua on New Guinea.
- 1987 - Programming language Perl was released by Larry Wall.
Recent days: December 17 – December 16 – December 15