Certares, a private equity firm, completed the acquisition of AHI International, an operator of guided land and river journeys. Financial terms were not disclosed. Founded in 1962, AHI is a leading operator of guided land and river journeys for education-based affinity groups such as alumni associations, museums and cultural institutions. AHI designs differentiated travel programs that cater to the interests of its top-tier client organizations. All carefully crafted programs feature a strong educational component led by a multi-lingual network of travel directors.