You can go to the former Turkish fortress or to the Turkish Church.
Museum of history and economy of the Danube region
Izmail's oldest building is the small Turkish mosque, erected either in the 15th or 16th centuries, converted into a church in 1810 and currently housing a museum dedicated to the 1790 storm of Izmail.
The Intercession Cathedral
from 1822-36
Churches of Nativity
from 1823
Church of St. Nicholas
from 1833