Complex sentence: The racetrack got its name because it was built on the grounds of the old Hacienda of the Countess of Miravalle, the hacienda's old house still exists as the Russian embassy in Mexico.
Split into simpler sentences: The racetrack got its name from the grounds of the old Hacienda of the Countess of Miravalle on which it was built. The hacienda's old house still exists as the Russian embassy in Mexico.