Why is Oaxaca so famous?

I'm curious, could you elaborate on what makes Oaxaca such a renowned destination? What unique features or attributes does it possess that have contributed to its widespread fame? Are there any specific cultural, historical, or natural wonders that set it apart from other places? I'd love to gain a deeper understanding of the factors that have contributed to Oaxaca's popularity and what makes it a must-visit spot for travelers worldwide.