The webpage does warn that the calendar measures 28" by 10" (70 cm by 30 cm), but I hadn't realized how large that is--it's huge! So huge that they shipped it rolled up, in a box. But I'm sure I can flatten it back out again--I do own a copy of the full Brittanica encyclopedia in hard copy. :-)
As a calendar, it's a bit of a failure, because the section where the actual dates appear is small and narrow (about 4 inches tall--and each month includes the dates for both 2010 and 2011). But that means the costume photographs are HUGE--they take up most of the rest of each page. Better still, on the back of each month's page is a bit of descriptive text in English, with captioned photographs of various details of the featured costume.
I plan to try to photograph some of the back of the pages later, to give an idea of how much they have packed into this calendar. (Though, unfortunately, there are no citations to sources.) Given that's it's a two-year calendar as well, it's worth the money I paid for it.