Meta Llama 3.1-405B is a series of large multilingual pre-trained language models developed by Meta, including models with sizes of 8B, 70B, and 405B. These models feature an optimized transformer architecture, tuned through supervised fine-tuning (SFT) and reinforcement learning from human feedback (RLHF) to align with human preferences for helpfulness and safety. The Llama 3.1 model supports several languages, including English, German, French, Italian, Portuguese, Hindi, Spanish, and Thai. It excels in various natural language generation tasks and outperforms many existing open-source and closed chat models in industry benchmarking tests.