trivago is the world’s largest and most successful metasearch for hotels with more than 2 million daily users. The hotel search boasts 40 country platforms in 24 languages and integrates the prices of more than 200 booking sites. In order to guarantee the site’s availability and continued growth, a stable architecture is necessary. But which technologies need to be in place for this task? How many data centers are needed? How many servers are there? And what does "large" actually mean? Is it "just a website“ or is there more to it? This lecture will give a good overview of trivago’s architecture and structure.