Chicago exploration days

Single heavy atoms supported on thin carbon film were first imaged by Crewe, Wall and Langmore with their dark-field STEM. This glimpse into a hitherto invisible world we owe undeniably to Crewe's vision and determination, and to his gift to electrify, engage and encourage talented students. Since this successful event happened during my sabbatical stay in Crewe's group, the editors of this memorial volume asked me to write an account of its early history, which I gladly composed mostly from memory. The circumstances that led to my collaboration with Albert Crew in Chicago are reviewed, and the main project that we jointly embarked on the Chicago 1 MeV STEM is described. It is shown that the project was nearing completion and would have likely been successful, had funding been continued. The paper concludes with a tribute to Albert I wrote many years ago. -- Highlights: ►► Reasons and motivations for Crewe's interest in electron microscopy are reviewed. ► Reasons and motivations for Crewe's interest in electron microscopy are reviewed. ► Early theoretical work on STEM imaging is summarized. The design of the Chicago 1 MeV Scanning Transmission Electron Microscope is described. ► Construction details are illustrated. Reasons for the project not reaching a successful conclusion are given. ► Tribute is paid to Albert Crewe.