Although each famous crater looks different, they have the same basic circular shape. Visit the Rio Cuarto craters in Argentina (South America). Zoom in to see these oval-shaped craters.

What is the controversy surrounding these craters? What do you think?

The controversy behind this craters is that thanks to the angle of the object's impact they could be habitable. Also, they could study them more.

Explanation:

The reason behind this answer is that majority of craters have an angle of impact of aorund45º. While the craters in the province of Cordoba, Argentina have an angle of impact of 15º. MAking them really plain, so they could be habitable for several species. Also, the materials found in the place suggest nothing more than quartz, so they represent no danger to the inhabitants, humans, or not. But more importantly that they have only received one major research study. Instead of a big variety, and they could be studied with more detail.