Nostalgica is an app concept to travel in the past. The concept of this app is utopic. As user, you should be able to travel in any time set in the past and can see in in different through categories the trends, news, fashion, music and so on. The data should be get be all archives and memories of all the people - which is impossible and utopian. This app should give the feeling of nostalgic and be especially personal to someone and his/her memory and of the friend and family.
A prototype of this app can be seen here.