Gerhard Richter is one of the world's most important contemporary artists. But he is also his own harshest critic. Recently surfaced photos show works of art that he destroyed half a century ago. Today, they would have been worth hundreds of millions of euros.

There was the painting of a warship that had been hit by a torpedo. It was shown in 1964, in the first gallery show of a painter who was still unknown at the time. It looked serious and dramatic, with the calm water in the distance, the inconspicuous silhouette of the ship and, underneath it all, a gigantic explosion. But then it disappeared.

Another painting that vanished forever was a work entitled "Tame Kangaroo," based on a curious magazine photo that the artist called a "wonderful" model in 1964. The painting was priced at 1,100 deutsche marks at the time. That same year, he also exhibited his portrait of Hitler, painted in 1962. It also disappeared.

These are great, vexing works. If they still existed, they would be hanging in private collections or major museums. Today, their creator is the most famous German contemporary artist, and the one whose works fetch the highest prices. Indeed, Gerhard Richter is the most important painter of our time.

The lost paintings are from Richter's very important creative phase in which he opened up new horizons for painting. In the early 1960s, he began working from photographs. The motifs were usually blurred on his canvases, and much appeared in only shadowy outlines. Although they had something about them derived from traditional painting, his artworks were also excitingly contemporary.