Of all the bubbles that burst during the dotcom era, few popped louder than Gary Winnick’s Global Crossing. The California entrepreneur, who built a network of undersea fiber-optic cables, became one of telecom’s richest superstars. Though Global Crossing never posted a profit, its stock price grew and Winnick cavorted in a fleet of corporate jets and a $90 million Bel Air, Calif., estate. Before his debt-laden company collapsed in 2002, he reportedly sold Global Crossing shares worth $734 million. An SEC investigation found no fraud, and a class action lawsuit by employees was later settled. In his defense Winnick e-mailed, “Global Crossing succeeded in its original mission to build a global network accessible to all people on the planet.”

Today Winnick is plugged in to the latest hot trend, green tech. His company iCrete licenses software that helps concrete makers produce a better mix. ICrete’s formula is being used for the foundation of the Freedom Towers at Ground Zero. Says architect Frank Gehry, who has employed the technology for his own projects: “iCrete’s concrete is a big breakthrough, stronger and cleaner, cutting carbon emissions by 40%.” Let’s hope that his concrete company is built on a more solid foundation than was Global Crossing.