Short answers, pulled from the story.
The first land mine recorded was a wooden stake sharpened to a point buried in the earth to cripple the feet of an advancing army. This ancient concept of victim-operated traps dates back to the Roman Empire where fortifications were surrounded by goads, lilies, and abatis designed to slow enemies and make them vulnerable to projectiles.
Chinese military engineers began filling hollow cast iron cannonballs with gunpowder to create the first true explosive land mines in the fourteenth century. The Huolongjing, a military treatise from this era, described a mine triggered by a bamboo tube filled with compressed gunpowder and lead pellets sealed with wax and concealed in a trench.
By 1863 the German chemical industry had created trinitrotoluene or TNT which became the standard explosive for land mines after the First World War due to its stability and resistance to dampness. Guncotton invented by Christian Schonbein in 1846 was four times more powerful than gunpowder but it was dangerous to manufacture until Frederick Augustus Abel developed a safe method in 1865.
In the Second Battle of El Alamein in 1942 the Germans laid half a million mines in two fields five miles deep known as the Devil's gardens which accounted for 20 percent of Allied tank losses. The Germans became the most inventive and systematic users of land mines during the Second World War developing the Schrapnell mine also known as the S-mine which jumped to waist height before exploding to send thousands of steel balls in all directions.
The Ottawa Treaty which came into force on the 1st of March 1999 represents a global effort to prohibit the use stockpiling production and transfer of anti-personnel land mines. The treaty has been ratified by over 100 countries and the Landmine & Cluster Munition Monitor has recorded over 120,000 casualties from mines IEDs and explosive remnants of war from 1999 to 2017.
Since 1989 nearly 44,000 Afghan civilians have been recorded to have been killed or injured by landmines and explosive remnants of war averaging around 110 people per month. In 2017 at least 2,793 were killed and 4,431 injured with 87 percent of the casualties being civilians and 47 percent being children under the age of 18.