Here is a view of the romantic ruins of the Godesburg Castle.

The description on the back of the postcard translates as follows:
The Godesburg
The castle dates from the 11th century, was destroyed in 1503, completely devastated. Only the 30m tower beautifies the area and still provides a magnificent panoramic view.
This is number 110 in the series.

This time we see the massive rock along the Rhine known as the Lorelei.

The legend on the back is from a German poem, translated crudely as follows:
The Lorelei
The Lorelei waved from fading Stone,
Performance floods down her veil
And contributes to the listening land into
The gold melting blood of her songs.
She has sung in my lonely hour
Of home and hope and love;
There the words out of her mouth
Remain forever in our hearts.
— From the epic “Trutz Katz” by Jorg Ritzel
This is No. 105 in the series

Next is a view of the “Mouse Tower” a keep in the middle of the Rhine river on a small island.

The description on the back of this card, translated from German:
The Mouse Tower on the Rhine near Bingen received its present form in 1856, but has existed since the mid 13th century. The grisly legend, the scene of which it forms, Rutland tells in his book Tell Rhine. Today the Mouse Tower serves as a signal light for shipping. About Rudesheimer against the mountain we see the glorious ruins of the castle rock.
This is number 103 in the series.

Today I begin an artistic tour of the Rhein river, from art postcards purchased by a relative during a European vacation in 1930. Presumably, all the images date from at latest the 1920’s, but given they are artworks, could be significantly earlier. The physical cards themselves, however, are 1930 era.
The first place is Rheinstein Castle.

The back of the card has a legend in German, translated (poorly) as:
A jewel of the German past is Rheinstein Castle, like the nest of a bird of prey on a narrow, steep cliffs, rising high above the flowing waters of the Rhine.
It is number 93 in the series.