Akhlesh Lakhtakia, distinguished professor of engineering science and mechanics, delivered a colloquium entitled 'Negative refraction' at the Instituto de Física of Universidad Nacional Autónoma de México, Mexico City on May 25, 2006. He also delivered a colloquium entitled 'Emerging trends in research on sculptured thin films,' at the Instituto de Investigaciones en Materiales of the same university on May 26, 2006.