New Delhi, May 29 -- Residents near the estate have reportedly noticed a marked increase in private security activity since the sale, fuelling widespread speculation that Thiel intends to use the property as a permanent South American base.

Peter Thiel's Buenos Aires mansion carries considerable architectural prestige. It was originally designed by Alejandro Bustillo, the Argentine architect whose portfolio helped define the country's luxury built environment during the twentieth century. Bustillo's other works include the Llao Llao Hotel in Bariloche and the Mar del Plata Casino, two of Argentina's most recognisable landmarks.

The exterior of Thiel's Buenos Aires mansion retains its original European character, with symmetrical proport...