The Kitáb-i-Aqdas
121.O banks of the Rhine!   ¶90
In one of His Tablets written before the First World War (1914-1918), ‘Abdu’l-Bahá explained that Bahá’u’lláh’s reference to having seen the banks of the Rhine “covered with gore” related to the Franco-Prussian War (1870-1871), and that there was more suffering to come.
In God Passes By Shoghi Effendi states that the “oppressively severe treaty” that was imposed on Germany following its defeat in the First World War “provoked ‘the lamentations [of Berlin]’ which half a century before, had been ominously prophesied.”1
1 Shoghi Effendi, God Passes By, p. 226