Complex sentence: In 1902 the property that The Langham stands on was owned by the same family, the Clarks, who owned the prestigious Dakota, and is currently owned by the Manocherian family.
Split into simpler sentences: In 1902 the property that The Langham stands on was owned by the same family, the Clarks, who owned the prestigious Dakota. The property is currently owned by the Manocherian family.