The Battle of Isandlwana, South Africa

Fought on 22 January 1879, this was the first major battle in the Anglo-Zulu War between the British Empire and the Zulu Kingdom. 
Eleven days after the British began their invasion of Zululand, a Zulu force of some 20,000 warriors attacked a part of the British main column of about 1,800 colonial, native troops and around 400 civilians. 
Body of British soldier at Isandlwana 'identified' after 130 years
The Zulus were equipped with the traditional Assegai iron spears and cow-hide shields, but also some muskets and old rifle. 
The British and colonial troops were armed with the state-of-the-art Martini-Henry breech-loading rifle and two 7 pounder artillery pieces as well as a rocket battery. 
The Battle of Isandlwana (Original) art by James McConnell
James McConnell (1973)
Zulus killed over 1,300 british troops. The Zulu army suffered around a thousand deaths. 
The battle was a decisive victory for the Zulus and caused the defeat of the first British invasion of Zululand
Brian Palmer
The British army had received its worst defeat against a technologically inferior indigenous force. 
 Isandlwana resulted in the British becoming much more aggressive leading to a second invasion and the destruction of King Cetshwayo's hopes of a negotiated peace.