A major point of the above is that the winners of wars typically write the history books and their reverence and view of history may not be all that positive. Examples like that litter the pages of history including the Roman Empire, the Ottoman Empire and so on. Architecture is molded and shaped to this very day by countries generally take a dim view of religion and the associated architecture (the U.S.S.R./Russia, China, etc.) while there are other situations where architecture is protected and argued about by multiple sects or religious (the Middle East, etc.) and this has been true in the 19th Century and it remains true to this very day.
Another dimension of architecture for which examples from the 19th century are prevalent and easy to spot can be seen in the houses that architects build for themselves. One such house was the Bloemenwerf House on the outskirts of Brussels, Belgium. Designed by Henry van de Velde, the house is fairly large in nature but uses neutral colors and there are no gleaming or overarching towers or spires. Instead, the building is simply made of masonry and timber and is comprised of just two (albeit big) main floors (Great Buildings, 2014). However, even vast buildings can be fairly non-descript yet impressive. An example of this would be the beautiful Biblioteque Ste. Genevieve in Paris, France. There is nothing terribly opulent or fanciful about this library, but it is rather large and impressive despite this and boats a cavernous yet not warehouse-like appearance. Wrought-iron arches span the roof and simple lamps hang down from the rafters throughout the entire length of the building. Designed by Henri Labrouste and built in the 1840's and finished in 1851, the urban-dwelling library is quite impressive without really trying to be. It is impressive yet functional but is not trying all that hard to look that way (Great Buildings, 2014).
On the flipside of architecture blending in or not being flashy and different from churches or other structures that are standouts in the area are neighborhoods and areas where the entire area contributes to the dynamic and appearance of the city. Example would be colonial-era building of Virginia. Even newer buildings including those built in the 21st century are designed and structured to fit in with the work of the 19th century buildings of the United States. While not in the 19th century, the works of the Mayans and biblical-era buildings of the Middle East, including those for all sects and religions in the era including Islam, Judaism and Christianity, permeate all edges and areas of the city segment, the city at large or even the country. Many cities in Italy are full of culture and expansive to beautiful architecture and a lot of those structures and buildings were put up in the 1800's. That being said, architecture is not always about flash and opulence, as made clear by cultures that knowingly and intentionally stay away from being too flash or over the top and this is even true of their religions and other foundations for their lives and beliefs.
One last thing that can be discussed that greatly influenced culture and architecture during the 1800's (and before…as well as since) was the colonizing and settling of all corners of the world by the British, Spanish and French. While much of the colonization occurred before the 1800's, it was still in full effect for much of that century and that included the architecture. Even though the empires of those three countries fell away much like the Roman Empire before it, the presence of those countries lingers on and it is also obvious that a lot of the prior architecture was either blended with those empires or that they replaced it with their own. Indeed, much of what remained of those colonized areas was gone by the years of World War II. Just as a few examples, Puerto Rico is an American territory in the modern day but it a Spanish enclave until the end of the 1800's. India and Pakistan were controlled by Great Britain until World War II but India initially spun off and then Pakistan broke away from India. In short, the architecture for the preceding century and a half (which would have included the 1800's) included Indian, Muslim and British influences.
There is no doubt a lot of architecture in the formerly colonized countries, including a great amount from the 1800's, that was torn away or otherwise changed to meet the demands and preferences of the colonizing country. Indeed, what is now known as the United States was created just before the 19th century when the American Revolution happened. However, as the American nation has proven not all culture is destroyed and removed when the control of a country changes hands as a lot of the northeast still permeates with the same architecture. The United States had plenty of time to tear down the architecture and make their own during the 1800's. While they did do some of that, especially in newly controlled areas as the United States moved west, they certainly did not lay waste to what was created by Great Britain.
In the end, architecture is very much a function of power, control, religion and influence. Some cultures and groups make it a point to make their own statement while others just want to blend in. Some groups want to make their own architectural imprint the norm and the only source of influence while others want to eliminate any contrarian viewpoints and presences. As the years go on, tolerance and preservation of the treasures and buildings of yesteryear is more and more than the norm but crimes and misdeeds of prior years, including many in the 1800's, are still being corrected to this very day. Vulcanization and separation is still prevalent in some areas and cities as some areas are home to a specific religion or culture even in countries like the United States in cities like San Francisco and New York. However, many of the treasures of the 19th century remain to this day and are being preserved for the future.
Appendix I -- Catholic Cathedral Basilica of Assumption -- Baltimore, MD