Why did the spanish think they must be dreaming when they saw tenochtitlan?

When the Spanish conquistadors, led by Hernán Cortés, first arrived in Tenochtitlán, they were awestruck by its grandeur and sophistication. The city's impressive architecture, advanced infrastructure, and bustling markets starkly contrasted with their expectations of a native settlement. The sight of such a vast and organized civilization, complete with canals and large temples, seemed almost otherworldly, leading them to believe they must be dreaming. This overwhelming impression was compounded by the city's beauty and the wealth of the Aztec Empire.