The Gilded Age in United States history is the late 19th century, from the 1870s to about 1900. The term was coined by writer Mark Twain in The Gilded Age: A Tale of Today (1873), which satirized an era of serious social problems masked by a thin gold gilding. The Gilded Age was an era of rapid economic growth, especially in the Northern United States and the Western United States. The flourishing economic climate made possible for the very rich to build large houses, often designed by prominent architects of the day in eclectic styles. These buildings, today, form part of the United States's cultural heritage.