Complex sentence: Joan and Voltaire interact with ancient aliens living on the Mesh who fled Trantor when R Daneel Olivaw's terraforming robots arrived on Trantor more than 20,000 years ago.
Split into simpler sentences: Joan and Voltaire interact with ancient aliens on the Mesh. These aliens fled Trantor's physical space when R Daneel Olivaw's terraforming robots arrived on Trantor more than 20,000 years ago.