Who was a reason the Congo became the poorest and most dangerous places in the world in 1997? What did he do to make it so bad?

This is because The Second Congo War - also known as the African World War, the Great African War or the Coltan War - was the armed conflict that took place in much of the territory of the Democratic Republic of the Congo (former Zaire), after the First Congo War. This conflict began in 1998 and formally ended in 2003, when a transitional government assumed power under the terms of the Pretoria Agreement. The combatants came from nine nations (in addition to twenty different armed factions within the country), which makes it the largest African continental conflict known.

It caused the death of approximately 3.8 million people, most of them from hunger and preventable and curable diseases. Within these grave facts, this episode is considered the most critical within the so-called "Congolese genocide". This tragic number turned this war into the deadliest conflict since the Second World War, and that's not counting the millions of displaced people and refugees in neighboring countries.

Despite the formal peace reached in July 2003 in Pretoria and the agreement of the interveners to establish a government of national unity, state institutions remain weak and scarce in large sectors of the country, which still suffer sporadic outbreaks of violence. In 2004 it was estimated that about one hundred people died daily as a result of occasional skirmishes and lack of services and food. The forced migration of inhabitants continues to bleed the region in a crisis that seems not to end, while the elusive peace has not yet reached all regions.