St. Augustine's Church is a small neo-Gothic church built in 1863 for English-speaking visitors who came to Wiesbaden in its spa-town heyday. Its pointed arches and modest scale make it a quieter counterpoint to the grand theatres and colonnades nearby.
It is still an active English-speaking Episcopal church, so the best reason to come is either for a service or for a short architectural stop while walking the city centre. The building also says something useful about 19th-century Wiesbaden: this was a resort confident enough to build for a truly international crowd.