Because of their tremendous breeding potential and genetic diversity, many pests are known to withstand synthetic chemicals and bear offspring with a built-in resistance to pesticides.
Tens of thousands of dams, many built before seismic engineering came of age, have the potential to release tsunami-like flash floods in the event of a seismic breach.
Beyond the "old", we must recognize that AJAX is a new powerful and complex technology that, while built on old ideas, when used in practice, has the potential to introduce new vulnerabilities.