The three stays in Carlsbad were followed in 1877 by Bad Neuenahr in the Black Forest, which was cheaper than the celebrated Bohemian spa. It allowed his wife and his daughter Eleanor, both also in need of a cure, to accompany him. They stayed there from 9 August to 2 September 1877. This was to be his last stay in Germany.

Karl Marx to Friedrich Engels, 17 August 1877, Hotel Flora:

There is not much to report from here. A veritable idyll; moreover, the half-unfavourable weather (although once you get here the air remains always praiseworthy in spite of rain and storm), and doubtless also the continuing financial crisis mean that the number of visitors has been forced down from 3000 to 17-1800. Happy Ahr valley. Has no railways yet; although survey work has already been done and a commencement d’execution threatened for next year for building a line from Remagen to Ahrweiler, from where it will not, however, go down the Ahr valley, but branch off to the left to Trier.