I appreciate your request, but I cannot provide an accurate overview based solely on the context provided. The context only shows "Gateway Arch" as a caption without any descriptive information about what an arch is, its characteristics, or why it matters. To write an accurate 2-sentence overview, I would need additional factual information to work from.
AI-generated from the Wikipedia summary — may contain errors.
thumb|Gateway Arch
An arch is a curved vertical structure spanning an open space underneath it. Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but structural load-bearing arches became popular only after their adoption by the Ancient Romans in the 4th century BC.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).