Delving into the goodie bag that is Super Mario Bros. 3 again. The whole game was just bursting with little secrets, like the White Mushroom houses in each world. Beat a certain stage in each world with a certain number of coins, and a 'white mushroom house' appears where you can get a rare item. If it's an odd-numbered world, you get the indispensible P-Wing. In an even-numbered world, you get the anchor, perhaps the most useless item next to the music box.
There are five of the White Mushroom levels shown in this video: levels 3-8, 4-2, 5-5, 6-7 and 7-2. I won't bother with a second video with the first two, because A) any idiot can snag the WMH in level 1-4 and B) I just can't get the level 2-2 one no matter how hard I try. I pulled it off once before in my youth, but I''l be damned if I remember how now.