The globe on Hercule Poirot's desk is an ancient world globe with Latin text. It adds interest to his desk but is not much use as a map of the world for someone who values mathematical precision and accuracy. However it is highly visible on Poirot's desk in many scenes and one just like it can be found on eBay as I discovered.

Click here to see it on eBay
This ancient world globe on brass stand is about 8" tall and is stamped Made in Italy along with Mod. Dep.

The shape of the stand and the detailing on the map match the globe on Poirot's desk. It is for sale on eBay.com this week.