If Macchu Picchu was undiscovered then...?

Macchu Picchu was a royal retreat for the Incan king and family in South America. In the 1500s the Spaniards led the Spanish conquest and conquered the Incan empire. They destroyed artifacts and melted gold down to make Spanish doubloons. Macchu Picchu was undiscovered until the 1900s by American backpackers and it had been untouched and unfounded by the Spaniards or any other people. Do you think there may be other undiscovered ancient cities of past civilizations?