Simplify the following text for a Grade 13 native English-speaking person.
Original: In his book Russia at War 1941 to 1945 , Alexander Werth reported that while visiting Gdansk\/Danzig in 1945 shortly after its liberation by the Red Army , he saw an experimental factory outside the city for making soap from human corpses .
Simplified: In his book `` Russia at War 1941 to 1945 '' , Alexander Werth said that while visiting Gdansk\/Danzig in 1945 shortly after its liberation by the Red Army , he saw an experimental factory outside the city for making soap from human bodies .