Cool. I like it in Antigua. Nice town, very old, and very scenic. Nice view of lots of volcanos. I don't know about Atitlan lake. I know its a volcanic lake, and here is a list of the top ten listed by this web site. I was recently in Lake Coatepeque in El Salvador. Very interesting lake. Then went up to Cerro verde to view down the crater of Izalco volcano. Guatemala has it all asfar as lakes and volcanos. Have a nice trip.

Top 10 Amazing Volcano Lakes