European Emergency Number: 112
The European emergency number 112 can be called free-of-charge, 24/7 in any country within the EU (and Switzerland) to contact any emergency service: an ambulance/emergency medical services, the fire department, or the police. The number can be called directly, without a country code.  

A specially trained operator will answer any 112 call. The operator will either deal with the request directly or transfer the call to the most appropriate emergency service depending on the national organization of emergency services.  

Operators in many countries can answer the calls not only in their national language, but also in English or French. If the caller does not know where s/he is, the operator will identify where the person making the call is physically located and will pass it to the emergency authorities so that these can help immediately.

For more information please see the website of the European Emergency Number Association: 
http://www.eena.org/pages/useful-information#.WlYH9a7ibcs

U.S. Consulate in Vienna
For U.S. Citizens in need of immediate emergency assistance, please call +43 1 31339-7535
Monday – Friday 8:30 am – 4:30 pm.
After hours the duty officer should be called at: (+43) 31339-0.

All other inquiries: +43 1 313 397 535

Address: Parkring 12a (side entrance of Marriott Hotel), 1010 Vienna
Email: ConsulateVienna@state.gov