[nickff]

You've seen the only XB-70, prototype #1. Two prototypes were made, and the other was destroyed in a mid-air collision. There is a very good episode of the televison show "Great Planes" on the XB-70.

[6stringmerc]

Ah, so it would appear. Parked next to an SR-71 when I saw it. Many photos were taken that day. Thanks for the episode tip!