Basement exterior walls not showing in elevations

[DIY_Design]

When I create an elevation the basement (level 0) exterior walls do not display but the interior is displayed.  I can see them in 3D but they are just invisible in my elevations.  No idea why.  What am I missing?

[TeaTime]

When things aren't showing up, the first thing to look at is layers. Elevation views have their own layer set, so things may appear differently than in other views., and since they show in 3D but not elevation I assume this is the issue. Open an elevation and make sure both the Foundation and the Walls, Foundation layers are on.