If I was a betting man, and had only this picture to make my bet, I would say that this is an freeze-thaw crack - pressure from the soil outside the foundation pushing inward (hence the semi-circular pattern - not stair-step, not vertical or horizontal), so it might be a matter of some exterior grading/drainage work followed by an epoxy grout crack filler repair to remove moisture.I recommend you get it checked out - put a contingency in the contract that covers your bases, so you're only out a couple hundred bucks for a structural inspector. 

Horizontal/level doesn't matter.

Whitson Gordon (non BP Member)Pros: Basic is free with 60 MB of new uploads per month and sync across 2 devices Cons:Not designed for real estate Cost: $34.99 for Plus with 1 GB of new uploads per month with synch across all devices $69.99 for Premium with 10 GB of new uploads per month with synch across all devices and more featuresTrello - A Trello board is basically a web page containing lists laid out horizontally on the page so you can get a bird's eye view of your project.

I am just the mezz on this one... someone else will do horizontal and vertical...

You will need to have a horizontal fire rated floor of 1 hour per IBC 420.3 and 711.3. 

Don't like the Long Lot going backwards, prefer long lots horizontal to the road or roads on multiple sides of the property, for more entrances and splits. 

I would imagine that if one were to expand horizontally (like expand foundation and build or attach a new structure to an existing one), one would need to survey land...and this would more or less be considered along the lines of "new construction." 

The horizontal window here was original to the old house.

I had another thought on this subject too that may be useful for converting existing space... if either the building code or the fire protection requirements to have the attic sprinklered is triggered by square footage or volume of attic area, might want to look into seeing if it can be divided into smaller sections with rated assemblies... in short have a horizontal rated assembly (the ceiling) as well as vertical ones (at truss or rafter location).

Makes for a truly horizontal paycheck  (auto deposited in my acct of course!)