Andros island in the Bahamas has the largest collection of the blue holes. Andros is the largest island in the Bahamas and it more than 200 Blue Holes. Blue Holes are usually sink holes or underwater caves in shape of a circle.
Impact crater is a type of impact landform formed due to collision of astronomical objects. Impact crater is a circular depression formed by the hypervelocity impact of a smaller body.Folowing are the examples of impact craters on the Earth:Lonar crater – IndiaKaali crater – EstoniaKarakul crater – Tajikistan