At last, Landmarks. And five of them because why not. There are twenty-one of them so there are still plenty you haven't seen.
So, the card breakdown most likely as follows, given that there are 21
events Landmarks and 76 pieces of card art:
300 Cards:
- 24 Kingdom card piles of 10 cards each, 8 are split piles
- 21 Landmarks
- 15 Events
- 0 blank cards
This makes 300 cards even (with 11 cards per kingdom pile).
Here's the breakdown for the art:
- 24 pieces of art in the kingdom piles.
- 21 pieces of landmark card art
- 15 is the number of events needed to get 300 cards (using 25 kingdom piles only leaves you with 4 cards left for events, which is too low).
- 24 + 21 + 15 = 60 art, leaving 16 for the split piles
- It takes 2 additional pieces of card art per split pile (1 for the bottom card and one for the combined randomizer, assuming that's how they work), so that's 8 split piles to make the 16 remaining card art.
- I'm assuming no Alt-VP cards in this set, since there are already so many new ways to score and no piles with weird numbers of cards (e.g. Rats, Port).
If I'm right, that means there are:
- 16 unrevealed Landmarks
- 15 unrevealed Events (some of which will come up tomorrow)
- 5 unrevealed Split piles (with the 2 cards in each)
- 6 unrevealed regular Kingdom cards (1 card per pile)
- 48 total unrevealed cards/landmarks/events (we've seen 21 so far)
Unless someone has a more likely breakdown.

EDIT: 23 Kingdom piles with 6 split piles, 21 Landmarks, 20 Events, and 6 Blank cards is also valid, but does seem low on the Kingdom piles and a bit high on Events (also the same with 19 Events and 7 split piles).
EDIT 2: Well, with the Events and Castles preview with 13 Events and 8 Castles card artwork, that basically makes it 24 Kingdom piles (one being Castles victory pile), 5 split piles, 21 Landmarks, 13 Events, and 0 blank cards.