84166
They are believed to have been built thousands of years ago by an alien species known as the Heechee , but little else is known about them until an explorer discovers a Heechee ship , intact and operational , in one of the tunnels .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities:  
Answer:
 None