Endgame Study #3: White to move and draw

Thanks everybody. Its a very nice study. Few of you got it right. Anyways here is full solution. Hope you have the reddit PGN addon installed:

[pgn][Event "Mannheim"] [Site "?"] [Date "1914.??.??"] [Round "?"] [White "Mieses, J."] [Black "Post, E."] [Result "0-1"] [SetUp "1"] [FEN "8/1p6/8/2p4R/1kP5/3K4/p7/3B4 w - - 0 1"] [PlyCount "7"] [EventDate "1914.??.??"] [SourceDate "2005.01.24"]

{It's a position taken from a genuine historic game - one played exactly a hundred years ago. Four different opinions are quoted, each contradicting the previous one about who is actually winning. 1.) An amateur, who had strolled by the board, whispered to a friend: The black pawn on a2 is going to queen, and White can do absolutely nothing to stop it. So Black is winning!
2) His friend, a stronger player, didn't agree: "Come on, wake up! White plays 1.Rh7! a1Q 2.Rxb7+ Ka3 3.Ra7+ Kb2 4.Rxa1 Kxa1. It's a clear win for White!"
3) At the board White, an expert player, studied the position for a while and then resigned! He stretched out his hand and said to his opponent: It's quite hopeless, really. After 1.Rh7 you play 1...Ka5 2.Rxb7 Ka6 3.Rb8 Ka7 and I can't stop you from getting the queen. So Black obviously wins. 4) His opponent, who was an even stronger player, accepted his resignation and then, to the horror of the white player, said: "Actually I was just about to resign myself. I saw that after 1.Rh7! Ka5 you simply play 2.Rh8! The a-pawn is lost and the game is over. So actually White was winning." So who was right - or were all four wrong? I urge you to study the above position and draw your own independent conclusion. If you can solve the puzzle in your head you should give yourself a contortionist's pat on the back.} {Solution: the result is actually a draw!} 1. Rh7 $1 a1=Q $1 (1... Ka5 $2 2. Rxb7 (2. Rh8 $1 $18) 2... Ka6 3. Rb8 Ka7 $19) 2. Rxb7+ Ka3 3. Ra7+ Kb4 $1 {The key move overlooked by all.} (3... Kb2 $2 4. Rxa1 Kxa1 $18) 4. Rxa1 {stalemate!} (4. Ra4+ Qxa4 5. Bxa4 Kxa4 6. Ke4 Kb3 (6... Ka5 7. Kd3 Kb4 8. Kd2 Kxc4 9. Kc2 $11) 7. Kd3 Kb4 8. Kd2 Kxc4 9. Kc2 $11 {Carlos Mas.}) 0-1[/pgn]

/r/chess Thread Link - i.imgur.com