What is an LLM and Why Transformers Changed Everything

LLMs didn’t become magical overnight - one breakthrough called transformers quietly rewired how machines understand language. Over the past few years, Large Language Models (LLMs) like ChatGPT, Claude, and Gemini have redefined how humans interact with machines. Whether it’s writing code, summarizing research, or chatting naturally, these models rely on one central breakthrough - the transformer architecture. But to really appreciate why transformers changed everything, we need to peel back a few layers: what an LLM is, how it processes language, and what makes it so powerful.