Complex sentence: The city lies between a group of rolling hills with a distinctive rock formation (found only in 3 places in the world) and Ypacaraí lake and is known for its colonial architecture, along with its original cobblestone streets.
Split into simpler sentences: The city lies between Ypacaraí lake and a group of rolling hills with a distinctive rock formation, found only in 3 places in the world. It is known for its colonial architecture, along with its original cobblestone streets.