There is a lot of things that can be astonished in Greece.
One of them is the lacustrine caves at south Peloponisos in a n area called Lakonia,close to ancient city Sparti.You going in site with a canoe that takes 6-8 people.The total length is about 13,5 Km but only
1,2 Km is operating for public.
The caves are full with stalagmites and stalactites making a very beautiful environment that you never going to forget.