Andrew Jackson Downing, a renowned landscape architect and writer, is credited with raising awareness about the importance of preserving historic buildings and landscapes in the mid-19th century.

The Society for the Preservation of New England Antiquities, founded in 1885, is the oldest preservation organization in the United States.

Jacqueline Kennedy Onassis, former First Lady of the United States, played a pivotal role in mobilizing public support and securing funding to save Grand Central Terminal from demolition.

Edith Wharton, a celebrated novelist and preservationist, is often referred to as the 'Mother of Historic Preservation' for her tireless efforts to protect historic buildings and landscapes.

Louis Sullivan, a prominent architect and mentor to Frank Lloyd Wright, is widely recognized for his pioneering work in adaptive reuse, advocating for the repurposing of historic buildings to suit modern needs.

Christopher Alexander, an architect and theorist, is renowned for his book 'A Pattern Language', which promotes a holistic approach to architecture that considers human needs and environmental factors.

Joseph P. Riley Jr., a former mayor of Charleston, South Carolina, played a crucial role in preserving the city's historic district by advocating for its protection and implementing preservation policies.

David Dixon, an architect and preservationist, led the efforts to restore and revitalize New Orleans' historic district after Hurricane Katrina, focusing on preserving the city's unique architectural heritage.

W.E.B. Du Bois, a prominent sociologist and civil rights activist, was also a strong advocate for the preservation of African American landmarks and communities, recognizing their cultural and historical significance.

Kenneth Chorley, an architect and preservationist, played a key role in restoring and preserving the historic buildings of Colonial Williamsburg, Virginia, bringing the town's colonial heritage back to life.

John Gaw Meem, an architect and preservationist, dedicated his career to preserving and promoting the traditional architecture and cultural heritage of the American Southwest, particularly in New Mexico.

Arthur Ziegler, an architect and preservationist, is renowned for his work in preserving historic theaters and playhouses across the United States, recognizing their cultural and architectural significance.

Jens Jensen, a landscape architect and conservationist, was a strong advocate for the preservation of historic landscapes and gardens, recognizing their aesthetic and ecological value.

Albert B. Wells, an architect and preservationist, led the efforts to restore and preserve the historic buildings of Old Sturbridge Village, Massachusetts, creating a living history museum that showcases early American life.

Ada Louise Huxtable, an architecture critic and preservationist, played a significant role in raising awareness about the architectural heritage of the American Midwest and advocating for its preservation.