Which conflict was the longest in terms of number of years?
Early Muslim conquests
Franco-Prussian War
War in Afghanistan
The Civil War
War in Afghanistan
First and Second World Wars
Civil War
Franco-Prussian War
The Spanish Civil War
The War of 1812
The War in Afghanistan
Anglo-Zanzibar
War of the Spanish Succession
The Vietnam War
War in Afghanistan
First and Second World Wars
Yugoslav Wars
The Spanish Civil War
The Civil War
Franco-Prussian War
First World War
War in Afghanistan
Anglo-Zanzibar
American Civil War
World War II
World War I
War of 1812
War of the Polish Succession
First and Second World Wars
Yugoslav Wars
The Spanish–American War of Independence
The First and Second World Wars
Vietnam War
Civil War
The Vietnam War
The Spanish–American War
War in Afghanistan
War of the Spanish Succession
The Spanish Civil War
The Civil War
War of 1812
The First World War
Franco-Prussian War
Anglo-Zanzibar
First and Second World Wars
Yugoslav Wars
Yugoslavia
The War in Donbass
First World War
The American Civil War
War in Afghanistan
The First and Second World Wars
World War II
World War I
The First and Second Balkan Wars
Yugoslavian Civil War
First and Second Balkan Wars
The Spanish Civil War
Civil War
First and Second Chechen Wars
War of the Polish Succession
First and Second World War
War of 1812
The Vietnam War
The Second Boer War
Vietnam War
Anglo-Zanzibar
Yugoslavia
First and Second World Wars
War of the Spanish Succession
War in Afghanistan
Yugoslav Wars
The Civil War
The First World War
The First and Second Balkan Wars
Napoleonic Wars
Franco-Prussian War
First and Second World War
First and Second Balkan Wars
First World War
Yugoslavian Civil War
Franco-Prussian war
The First and Second World Wars
First and Second Chechen Wars
World War II
World War I
Yugoslav War of Independence
War of 1812
War in Afghanistan
Yugoslavia
Yugoslav Wars
Civil War
The Spanish–American War of Independence
War of the Sixth Coalition
First and Second World Wars
The Vietnam War
Anglo-Zanzibar
The Second Boer War
The American Civil War
The Civil War of the Philippines
First and Second Chechen War
Vietnam War
War of the Spanish Succession
First and Second World Wars.
The First World War
The Spanish Civil War
The First and Second Balkan Wars
First and Second World War
The Civil War
The War of the Pacific
The First and Second Chechen Wars
Yugoslav Wars of Independence
Franco-Prussian war
Yugoslavian Civil War
War in Afghanistan
The Spanish–American War for Independence
The First and Second World War
The First and Second World Wars
First and Second Balkan Wars
Yugoslavia
War of 1812
The War in Afghanistan.
The Spanish–American War
War in Donbass
First World War
First and Second Chechen Wars
World War II
World War I
The Civil War in Vietnam
Franco-Prussian War.
The First and Second Balkan War
First and Second World Wars
The War of Independence
The Spanish–American War of Independence
Anglo-Zanzibar
First and Second Chechen War
War in Afghanistan.
Civil War
War of the Pacific
The Vietnam War
First and Second Balkan War
War in Afghanistan
Franco-Prussian war
The Second Boer War
The First and Second World Wars.
The First and Second Balkan Wars
Yugoslavia
First and Second World War
Yugoslav Wars of Independence
Vietnam War
The Civil War
The First and Second World War
The Civil War of the Philippines
Yugoslav War of Independence
Yugoslavian Civil war
War of 1812
First and Second World Wars.
The Spanish Civil War.
The American Civil War
War of the Six-Day War
First and Second World wars
Civil War
Franco-Dutch War
First World War
The Civil War of 1812
The First and Second World Wars
The Spanish–American War
The First and Second Balkan War
War in Afghanistan
The First World War
The Spanish Civil War
First and Second Balkan Wars.
First and Second World Wars
Anglo-Zanzibar
War in Afghanistan.
War of the Pacific
The Civil War in Vietnam
The Second World War
Franco-Prussian war
Franco-Prussian War.
The Vietnam War
War in Donbass
The Civil War
Civil War
The First and Second World War
First and Second Balkan Wars
War of the Spanish Succession
Yugoslavian Civil war
War of 1812
The First and Second World Wars.
The Spanish Civil War.
World War I.
The Civil War of the Philippines
First and Second Chechen Wars
War in Afghanistan
First and Second World War
The First and Second Chechen Wars
Spanish–American War of Independence
The Second Boer War
The American Revolutionary War
The Second Boer War.