This is crazy. Articles already start with perfectly good summaries. look at your example:

en.wikipedia.org/wiki/World_War_II

the very first paragraph is this:

World War II[b] or the Second World War (1 September 1939 – 2 September 1945) was a global conflict between two coalitions: the Alliesand the Axis powers. Nearly all of the world’s countries participated, with many nations mobilising their resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of over 60 million people. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were put on trial for war crimes.

The minutia is there if you want, but it’s not necessary if all you need is the summary.