The 140-year-old Buenos Aires Zoo is shutting down after a string of preventable animal deaths

Zoos are a polarizing topic: They let you get close to wild animals, but they also confine animals into small and artificial environments.

Last week, Horacio Rodriguez, mayor of Bueno Aires, announced that the city will be shutting down its 140-year-old zoo due to a series of ongoing difficulties.

In 2012, a polar bear, named Winner, died at the zoo over the Christmas season from heat exposure and poor enclosure conditions. Winner was only supposed to be at the zoo as a featured attraction from another facility.

Sandra, an orangutan, was another problem. In 2014, an Argentina court ruled that Sandra had thoughts, feelings, and some basic rights and found that she was being subjected to unjust confinement at the zoo. However, despite the ruling, Sandra was never actually moved.

The mistreatment of Winner and Sandra weren't isolated cases. Two sea lions died at the zoo in 2015 after being forced to perform 15 consecutive shows. In the past few years, other zoo animals - including kangaroos, camels, reptiles, hyenas, and pumas - have also died.

Now, the zoo is opting to move 2,500 of its animals to other parks in order to protect them.

However, about 50 animals, including Sandra, will have to remain where they are. Zookeepers worry that moving them to new homes will put undue strain on them due to their age and health.

Following the move of most of its animals, the Buenos Aires zoo will be revamped and converted into an ecological park. The new park will be "a place where children can learn how to take care of and relate with the different species", Mayor Rodriguez told The Guardian. "What we have to value is the animals. The way they live here is definitely not the way to do that."

The zoo had recently experienced a decrease in visitors and revenue, resulting in the poor maintenance of its enclosures. Animals suffered as a result, and workers complained about the string of preventable animal deaths that occurred. Rodriguez described this as "degrading for the animals, it's not the way to take care of them."

Public outcry against zoos has been growing since a Copenhagen zoo killed a giraffe in 2014. The following year, Costa Rica tried to close down its zoos, but the attempt failed after the motion lost in court. Now, after the recent Harambe incident in Cincinnati, zoos and their treatment of animals are once again in the spotlight.

For many animal activists, Buenos Aires is seen as a step in the right direction, one that they hope will lead to other positive steps in the future.