The value of the gross estate shall include the value of all property to the extent of any interest therein of the surviving spouse, existing at the time of the decedent’s death as dower or curtesy, or by virtue of a statute creating an estate in lieu of dower or curtesy.
26 U.S. Code § 2034. Dower or curtesy interests
1962—Pub. L. 87–834 struck out provisions which excepted real property situated outside of the United States.