Simplify the following text for a Grade 13 native English-speaking person.
Original: Volgograd , formerly called Tsaritsyn ( ; 1589 â `` 1925 ) and Stalingrad ( ; 1925 â `` 1961 ) is an important industrial city and the administrative center of Volgograd Oblast , Russia .
Simplified: Volgograd formerly called Tsaritsyn ( 1589 â `` 1925 ) and Stalingrad ( 1925 â `` 1961 ) is an important industrial city and the administrative center of Volgograd Oblast , Russia .