Have you seen History Pockets? Check them out here: http://www.evan-moor.com/search?q=Name:%22History%20Pockets,%20Grades%201-3%22
I don't know about you, but I thought these looked like lots of fun and like something my kids would all love doing. The problem? Well, there were two actually. Number one, there weren't any History Pockets for the time we were studying that I could find. And number two, the most important reason, I was out of money to spend on curriculum for the year! :O
So I came up with a variation of the idea that I like to call my History Folders. In it, we put a map of the area we were studying at the time (China) with the Mongol Empire colored in, a Chinese flag, a timeline of Marco Polo's adventure, a map of his route, and a notebooking page that included information about Genghis Khan.
You can see the timeline notebooking page here: http://notebookingfairy.com/pixiedust/all-purpose/timeline-notebooking-page.pdf
I made the Mongol and Genghis Khan covers and notebooking pages: https://docs.google.com/file/d/0B1QxG4LMyj4UNFk1b0FDQVBRYWc/edit?usp=sharing
Homeschool Share has a complete explorers unit (which includes Marco Polo) here: http://www.homeschoolshare.com/explorer_unit.php
And the Chinese flag can be viewed here: http://www.enchantedlearning.com/asia/china/flag.shtml
Here is our finished product: