Theo Albrecht Jr. and the heirs of his brother, Berthold, inherited one of the world's great retail fortunes, which grew from a corner grocery store in Essen, Germany, started in 1913. After World War II, their father, Theo Sr., along with his brother, Karl, took over the store and propagated the discount revolution in German retailing -- building their Aldi supermarket chain based on a no-frills, low-price strategy similar to Wal-Mart. In 1961, the brothers split ownership: Karl took the stores in southern Germany, plus the rights to the Aldi brand in the U.K., Australia and the U.S., while Theo Sr. got the stores in northern Germany and the rest of Europe. In 1971, Theo Sr. bought U.S. grocery discounter Trader Joe's. Together, Aldi Nord and Trader Joe's had estimated sales of around $40 billion in 2013. The businesses are owned through a family foundation set up by Theo Sr. after he was kidnapped for 17 days in 1971. Theo Sr. died in 2010, at the age of 88, and Karl died in 2014, at age 94. Like the family patriarchs, the Albrecht heirs maintain a decidedly low profile, and not much is known about them personally. Theo Jr. and his mother, Caecilie, sit on the board of trustees of the family foundation.