El Castillo Hotel Fabrega Organizational Center, Medieval-style hotel in Valle Hermoso, Argentina.

El Castillo Hotel Fabrega is a stone and brick building with fortified towers situated on about four hectares in Valle Hermoso. The structure contains over 40 rooms designed for accommodation and training purposes, with spaces arranged throughout the property for different activities.

Built around 1870 as the main house of the Las Playas estancia, it was enlarged in the early 20th century into the Hotel Monte Olivo. Italian immigrant José Ferrarini bought it in 1939 and closed it for over thirty years. From 1970 to 2000 it served as a metalworkers' union holiday camp, then reopened in 2006 as a hotel and training center after a four-year restoration.

The building's name comes from the Fábrega family, who led its four-year restoration from 2002 using only local labour. Since 2006 it has run seminars on leadership, negotiation, teamwork and decision-making, and each organisation that books it has exclusive use of the whole property. Family programmes are offered for two months a year, during school holidays.

The property offers accommodation especially during school holidays and regularly hosts group events, corporate training, and workshops year-round. Visitors should know that the place operates mainly for organized groups and planned activities, so independent visits may not always be available.

The restoration begun in 2002 took four years and was carried out entirely by local labour, artisanally directed by an Argentine family. The same local team then staffed the hotel. In 2013 the British Argentine Chamber of Commerce awarded El Castillo its First Prize for Sustainable Leadership.