TheHolocaust was a Genocide to kill Jews that was lead by German leader Adolf Hitler. To Adolf, Jews were inferior and he did not want them to live. He blamed them for the loss of a battle in 1983, and he wanted a 'pure' German race.
Concentration Camps are camps that Jews were sent to to be killed, or gassed. A lot of horrible acts happened in these camps. Jewish people were staved, beaten, mistreated, and killed. The camps held about 45,000 people each camp. Not just Jews were placed in these camps, people who were criminals and Homosexuals were also sent to camps.
How are these camps maintained
Concentration Camps are mostly maintained by paid keeps-men or maids, people who are rewarded for cleaning and taking care of places. That is now at least, back then they made the people who were sent there clean and some German's would clean up the deceased from the grounds.
More than 44 million people visited Auschwitz since it opened. In 2014 more than 1.5 Million people visited. Mostly people from an educational profession come to visit.
Concentration Camps should be preserved because they are a important piece of history. They mark a massive event that changed the world today. Not only to educate but to save the past of wars.