For academic and research purpose I could visit several countries (Shown on the map below).
Countries visited: United States, Canada, United Kingdom, Australia, Germany, Japan, Switzerland, Netherlands, Belgium, Italy, Greece, Spain, France, Austria, Sweden, Denmark, Norway, Czech Republic, Slovakia, Hungary, Vatican City, Russia, South Korea, China, Taiwan, Hong Kong, Vietnam, Thailand, Cambodia, Malaysia, Singapore, Indonesia, United Arab Emirates, Saudi Arabia, Egypt, Qatar, Uzbekistan, Maldives, Sri Lanka, Nepal, Bhutan, India.
Districts visited (Bangladesh):