Zoo de Madrid, lions and tigers (3D)
Very nice 3D card (lenticular printing) showing a range of photos of lions and tigers, depending on your perspective. Two are available. One was mailed from Spain in 2012 with two stamps (three, if you count the se-tenant large stub of one of them) (Grade: 1, $5). The other was mailed in 2013, with three stamps and full postmark (Grade: 1, $6).