What's an interesting historical topic to do an Investigastion on?

It might be easier if you focus on your personal interests rather than ask strangers for a really random topic. AT least if you have a modicum of interest in your subject, the paper will be easier to write and the end product will be a tad more satisfying.

Can you whittle the period down to a few decades? What country do you live in? If you write a paper on a regional bit of history than finding the appropriate primary sources for the history paper will be that much easier.

Babylonian Chiropody.

How about the topic of Stonehenge in Britain?

Use LIDAR techniques to identify and locate the medieval outlines and innards of some city in your country. If youre in the UK, many cities have preserved ruins outlines an walls that are rubblized and these are buried beneth existing roads. Using LIDAR (you hve to larn the techniques of "Slope shaed" or "Hill shade" outlines and from these you can traace the boundaries as they changed through history.

In the US, th cities (like Philadelphia or Boton) go back severl centuries to th precolonial times and many minor soil disruptions that point to old structures (which can be researched as to their place names), and these can be mapped on top of existing city streets.
Much work in archeology and hitorical bounary id will be dependent on LIDAR mapping.

Look it up.
USE OF LIDAR IN ARCHAEOLOGY
LIDAR TECHNIQUES IN IDNTIFYING COLONIL ND PRECOLONIAL SETTLEMENTS IN THE PIEDMONT OF (Va, Md, Pa, NJ, NY, Conn)
It a skill that can lea to a career