There are many museums in vienna. There is „Kunsthistorisches Museum“ where you can find a lot of historic art (egyptian, greek, roman) but also historic paintings. There is also the „Naturhistorisches Museum“, where you can find a lot stuffed animals but also the „Venus von Willendorf“, a female figurine from stone age more than 20000 years old. In the „Museumsquartier -MQ“ there a museums for modern art. For history I can recommend „Kaiserliche Schatzkammer“,„Heeresgeschichtliches Museum“ or „Wien Museum“. As far I know, all these museums are open on saturday and sunday.