What are good offline turn by turn navigation apps?

[AC Question]

I'm looking for an navigation app whitch features an offline turn by turn navigation.
Not only the Maps data should be offline. Also calculating the best routes should work offline since i'm traveling a lot around Europe i don't want to spent so much money on roaming fees.

 

[ssenemosewa]

I use and am pretty happy with CoPilot.

 

[TJA3500]

Google Maps
You can download the city or area on wifi and then use offline. Offline data will expire in about 29 days.
Or
Turn data on and start your trip then you can turn off data and will still get turn by turn navigation. Keep GPS on high accuracy.

 

[sydneycooper1979]

I would also recommend google maps.