upside down
adverb /ˌʌpsaɪd ˈdaʊn/
  /ˌʌpsaɪd ˈdaʊn/
Idioms - in or into a position in which the top of something is where the bottom is normally found and the bottom is where the top is normally found
- The canoe floated upside down on the lake.
 
Oxford Collocations DictionaryUpside down is used with these verbs:- hang
 
Word OriginMiddle English: originally up so down, perhaps in the sense ‘up as if down’. 
Idioms 
turn something upside down 
- to make a place untidy when looking for something
- The police turned the whole house upside down looking for clues.
 
 - to cause big changes in a person’s life that upset and confuse them
- His sudden death turned her world upside down.