Purple Carrots?

Courtesy of the World Carrot Museum 
I was drinking some juice today that contained purple carrots. What's that all about? I looked online and apparently carrots come in a few colors. Who would have thought?  According to World Carrot Museum,

"Have you ever seen a purple carrot? How about white, yellow, red or black? Most people haven't, even though such carrots have existed for hundreds of years. . . Carrots were originally purple or red, with a thin root. The orange colour did not become popular until the 1500's when patriotic Dutch growers developed the vegetable by selective breeding to make it less bitter than the yellow varieties, and then it was adopted it as the Royal vegetable in honour of the House of Orange, the Dutch Royal Family."