Couple of pics. This first one is my Focus bike with 700c wheels. It's actually a cross bike but I'm using it as a road bike right now so I've removed the Rocket Ron cyclocross tires and put on a set of 700c x 32 Continentals. Look closely at the picture and you will see the rim says 700c tire size and the black lettering on the tire shows 622 (the wee letters) AND the 700x32 marking.
This bike is my old 'cross bike. I took the 700c Rocket Ron's off my Focus and put them on these wheels. The wheels are Spinergy Xyclone 29er mountain bike wheels. 700c tires on 29er wheels - perfect fit as long as they are wide enough.
This is a 26" mountain bike tire. It's a kenda small block 8 - my fav. In this picture you can see both the 559 marking (fairly large here, but sort of blended into the tire color-wise) and the 26" marking.
Oh by the way... A lot of 27.5 bikes will actually accept a carefully chosen 29er wheel with a slick tire provided you are running disc brakes. I've seen that one done a few times as well for a pretty darn quick "roadie" mountain bike.
angela