I did my 14 ATPL exams in the UK. It was about 6-7 months of full time studying at home (I did distance learning). I used Bristol Groundschool, and they were great. They had us come to class for 2 weeks and then sit the exams for a week. We did that twice.

Now, if you already have an ATP or ATPL from another country (such as the FAA ATP), there is no requirement to sit in the classroom prior to sitting the exams. You may self certify (at least in the UK, I don't know about Germany).

The UK CAA sets up a testing facility in Florida regularly.

If you want the EASA ATPL, it WILL consume a lot of time.