Complex sentence: After the erection of the Berlin Wall in 1961, emigration except for ethnic migration reasons mostly halted from east-to-west, though a few thousand escape attempts from East Germany occurred, including those by defecting border guards.
Split into simpler sentences: After the erection of the Berlin Wall in 1961, emigration except for ethnic migration reasons mostly halted from east-to-west. A few thousand escape attempts from East Germany occurred, including those by defecting border guards.