Now back to your regularly scheduled "Cards I Love"!
This one is from the favorites tag. I have so many awesome cards from those tags. For a while I was doing mainly tagging instead of sending officials, but now I have gotten back into sending officials. The thrill of picking an address and not knowing where or what kind of person it's going to be is my favorite part of postcrossing. I love that even more than getting awesome cards (which comes in a close second :).
Made that much more awesome by these stamps:
Top left: Europa stamp issued in May 2011. I'm not sure what the image is of, though.
Top right: One in a set of three endangered animals from 2007: snow leopard (Uncia uncia)
Bottom left: From 1998, but I don't know what it is of.
Bottom right: Sixth definitives series from 2009 - Russian Kremlins. This is Kazan Kremlin. See other kremlins from this series here and here.