Peter Thiel has quietly dropped $12 million on one of Buenos Aires’ most storied mansions — and the city’s luxury real estate market may never be the same. The PayPal co-founder, Palantir chieftain, and early Facebook backer — whose net worth eclipses $30 billion — has acquired a grand estate on Dardo Rocha Street in Barrio Parque, according to Forbes Argentina.  The home is in the rarefied enclave tucked inside Palermo Chico that serves as the closest thing Buenos Aires has to a plutocrat’s row. The property sits directly across the street from the residence of Argentine entertainment legend Susana Giménez. Neighbors have already noticed an uptick in private security personnel shadowing the grounds. Thiel did not respond to a request for comment.​​​​​​​​​​​​​​​​ Billionaire investor Peter Thiel has purchased a roughly $12 million mansion in Buenos Aires’ ultra-exclusive Palermo Chico enclave.…