company was awarded the contract to manufacture all of the bronze historical markers for the Texas Centennial. Since then thousands of cast aluminum historical markers have been provided for the State of Texas. In 1976, the company was selected to manufacture all of the historical markers for the Bicentennial. Recorded Texas Historic Landmark Recorded Texas Historic Landmark is the highest designation given by the Texas Historic Commission for significant structures in Texas. State Antiquities Landmark The THC may designate certain locations as State Antiquities Landmarks provided that they are not located on federal lands. These locations may fall into one of two categories: Historic buildings which must also be listed on the National Register of Historic Places and which are publicly identified. Archeological sites, which may not necessarily have NRHP listing, and whose locations are not available to the general public in order to avoid vandalism. Designation as a State Antiquities Landmark does not prohibit the destruction or modification of such a structure or location. Instead, the designation requires a permit for any modification subject to public review by the THC. Headquarters complex The commission has main offices in the Austin Complex in downtown Austin; the complex includes the Carrington-Covert House at 1511 Colorado Street, Luther Hall, Gethsemane Lutheran Church, Elrose Building, and the Christianson-Leberman Building. The Carrington-Covert House was turned over to the commission to serve as the agency's headquarters in 1971. Gethsemane Lutheran Church was restored to serve as offices of the agency in 1970 and 1971. Friends of the Texas Historical Commission Incorporated in 1996, the Friends of the Texas Historical Commission (FTHC) is a 501c(3) tax exempt nonprofit organization, further designated as a 509(a)(1) and 170(b)(1)(A0(vi) Public Charity, whose purpose is to develop private philanthropic resources to assist the Texas Historical Commission with its mission to identify, preserve, and protect our history—providing a lasting legacy for future generations. FTHC secures contributions to support the programs, projects, and activities of the Texas Historical Commission not provided for in the state budget. Despite its name, the Friends is not a membership organization. Over the past two decades, FTHC has helped secure more than $10 million to support THC projects and programs, including the 17th century La Belle shipwreck excavation in Matagorda Bay, the Fort St. Louis excavation, the Red River War Battle Sites Project, Texas in the Civil War and World War II Initiatives, the Texas Courthouse Stewardship