I arrive at Frankfurt international airport in the morning (9 am) and I have to wait 10 hours until my next flight. Also I don't have a visa to get out of the airport. What is the best way to get some sleep in the airport?
According to sleepinginairports.net, there are some seats without armrests in the hall between Terminal C and B, and security and cleaning staff will probably not bother you. Additionally, there are two lounges that are open to everyone (for a fee)