Lamberti Church
This church was the main reason for my visit to Oldenburg. I needed photos for my book. It is a remarkable example that shows how style and idea of protestant church architecture changed in the run of the 19th century.
From the outside, the church looks like just another of those late 19th century neo-gothic churches that can be found everywhere. However, the neo-gothic facades cover a building and interior which is 80 years older and surprisingly different.
Oldenburg's medieval parish church was changed into a neoclassical building in 1791-1795. The interior is a round hall undernath a huge dome which follows the model of the Pantheon in Rome. The steepleless outside looked like an antique temple.
Three generations later, style and taste had changed. Medieval styles had become popular and people wanted their place of worship to have a more 'church-like' appearance. So the existing neoclassical church was covered with new facades in gothic style. Works started in 1873 and were, with some interruptions, finished in 1893. The interior was left untouched and still shows the late 19th century style, although some changes were done during the renovation of 1966-1971.
More photos in the travelogue

Lamberti church, dome
Lamberti church
Meeting locals at Schlossgarten pond
Palace