Complex sentence: At Riga on the afternoon of June 29th, the Germans crossed the railway bridge over the Dvina and on 30 June Soviet troops withdrew on the right bank of the river and by July 1 were in retreat to Estonia.
Split into simpler sentences: At Riga on the afternoon of 29 June, the Germans crossed the railway bridge over the Dvina. On 30 June Soviet troops withdrew on the right bank of the river, and by July 1 were in retreat to Estonia.