"In the footsteps of the history of Łódź" is an application in the form of an audio guide that allows you to independently visit the Radegast Station and the Roma Forge in Łódź using mobile devices.The application presents the history of Łódź Jews and life in the ghetto created in 1940.By scanning the plates with QR codes, the lecturer-guide acquaints the user with audio and documentary materials about memorial sites, showing the user around all the locations and elements of the museum exhibitions. The audio guide is pointingalso for users the location of exhibitions and allows easy navigation to them from any point. The menu and content are available to visitors in Polish and English. For people with special needs, the application offers the possibility to change the visibility options by increasing the contrast and the size of the letters. Additionally, the audio materials have the option of displaying subtitles.The "Traces of the History of Łódź" application was created thanks to co-financing from the budget of the City of Łódź in cooperation with the Museum of Independence Traditions in Łódź.