The main center for information (walk-ins only) is the Vienna City Tourist Office, open daily 9-7 and centrally located between the Hofburg and Kärntnerstrasse.
Ask at tourist offices or your hotel about a Vienna-Card; costing EUR 18.50, the card combines 72 hours' use of public transportation and more than 200 discounts listed in the 104-page Vienna-Card Coupon Book, which every Vienna-Card purchaser receives free of charge. The Vienna-Card is also available at all sales offices or information booths of the Vienna Transportation System (for example, Stephansplatz, Karlsplatz, Westbahnhof, Landstrasse/Wien-Mitte) or from outside Austria with credit card, call (0043-1-798-44-00-148).
If you've lost something valuable, check with the municipal Zentrales Fundservice. If your loss occurred on a train in Austria, call the central number and ask for Reisegepäck. Losses on the subway system or streetcars can be checked by calling the Fundstelle U-Bahn.
Fundstelle U-Bahn (01/7909-43500). Reisegepäck (Central Train Information) (05/1717). Zentrales Fundservice (Bastiengasse 36-38, 18th District/Währing. 01/4000-8091; 0900-600-200 from elsewhere in Austria. Mon.-Wed., Fri. 8-3:30, Thurs. 8-5:30).
Vienna City Tourist Office (Am Albertinaplatz 1, 1st District. 01/24-555. 01/216-84-92 or 01/24555-666).