The most interesting thing to see in Odessa is the old town itself. The city was once the center for trade for the Russian Empire as well as an intellectual and artistic centre prior to the revolution and during the Soviet Union. Much of the grandeur of the city dates from the period before the Soviet takeover and subsequently Odessa shows its age.
The economic hardships that befell the city falling the collapse of the Soviet Union in 1992 have left vast portions of what was a magnificently wealthy old city in a state of total disrepair. The old city though is quite clean and feels very safe so it makes for a good two days worth of casual unguided wandering particularly with the wide tree lined avenues and large open parks.
In the much smaller and better kept part of the old town there is a large and beautiful Opera house and some very nice parks. There is also one main street leading through the centre that is vibrant with people selling street goods to tourists.
If you're looking for a nice route in a city center, try go from Grecheskaya square through Gavannaya st., then onto Gogolya street, in the end of which turn right and you will see Tyoschin bridge Mother-in-law bridge. Walk through the bridge and take a stroll along the Primorskiy boulevard. In the end of the boulevard you'll see the city hall. Turn right and go up to the Opera House, from where you can get to Deribasovskaya street. It's especially beautiful in the evening.
museums
Also there are many interesting museums in Odessa.
Museum of Western and Eastern Art
Muzey Zapadnogo i Vostochnogo Iskusstva. Perhaps the most interesting. You can see paintings by Aivazovsky and Caravaggio as of 9-1-09 no Caravaggio and other famous artists.Literature museum
at the very beginning of Lanzheronovskaya street. Features a 100 year walk through the history of Odessa in literature.Maritime museum
just between the Opera House and Literature museum. Houses a history of Marine Fleet.Archaeology museum
just around the corner from the literature museum.Picture gallery
at the very beginning of the Sofievskaya Street. Once a palace of Prince Pototskiy, features a huge collection of Russian artist paintings.Museum of the cinema
(http://en.wikipedia.org/w...) at 33 French Boulevard. With more then 10,000 works on display, the museum is a testimony to the history and cinematic activity in Odessa. Here you can find historic materials, from the invention of cinema, to the postmodern, digital and avant-garde.Odessa region museum
established since 1956, describes the history of region from the Dark Ages from the 12th century to present days. Has a few exhibitions and present halls. Is situated in the center of the city, in the former palace of Novikov.