Alatsee
{{Infobox lake
| name = Alatsee
| image = Aerial image of the Alatsee (view from the southwest).jpg
| caption =
| image_bathymetry =
| caption_bathymetry =
| location = Ostallgäu, Bavaria
| coords = {{coord|47|33|39|N|10|38|22|E|region:DE-BY_type:waterbody_source:dewiki|display=inline,title}}
| type = meromictic
| inflow = groundwater
| outflow = Faulenbach
|pushpin_map=Bavaria
| catchment =
| basin_countries = Germany
| length = {{convert|490|m|abbr=on}}
| width = {{convert|290|m|abbr=on}}
| area = {{convert|12.00|ha|abbr=on}}
| depth = {{convert|15.3|m|abbr=on}}
| max-depth = {{convert|32.1|m|abbr=on}}
| volume = {{convert|1840000|m3|abbr=on}}
| residence_time =
| shore = {{convert|1.3|km|abbr=on}}
| elevation = {{convert|868.0|m|abbr=on}}
| frozen =
| islands =
| cities =
| reference =
}}
Alatsee is a meromictic lake in Ostallgäu, Bavaria, Germany.
At an elevation of {{Convert|868|m|ft}}, its surface area is {{Convert|12|ha|acre}}.
Many divers have died or disappeared mysteriously in the lake due to the toxicity of the organisms living in the lake. These organisms create the "blood cloud " that occurs quite abundantly throughout the year.
This lake supposedly holds Hitler's gold.{{Ostallgäu-geo-stub}}