By Plane! If you have to money to go, of course. (Or boat...)
Yes, a US citizen can travel to Germany.
Latvia is part of Schengen Agreement, just as Germany is. So YES, you can travel to Germany on a Latvian Visa.
No. Why would he travel to Asia he is from Germany.
yes
Travelling by train is very common in Germany.
Most likely because he lived in Germany.
yes
The travel takes around 5 h and 40 min.
Politically speaking, technically, Germany is closer to the Philippines. However, it takes longer to travel east from Germany than to travel west from USA.
names of travel agencies
FCM Travel Solutions from Darmstadt- GERMANY
Yes, of course. It's in the EU.