Posted Monday, May 7, 2012 --- 7:10 a.m.

SPRING GREEN, Wis. (AP) -- Frank Lloyd Wright's estate, Taliesin, has started tours in south central Wisconsin.

The famous architect used the property in Spring Green as a laboratory of sorts, changing and expanding it until he died in 1959.

The National Park Service declared Taliesin a National Historic Landmark in 1976.

Taliesin Preservation, Inc. officials say they've added four specialty tours, each scheduled one Friday per month during the regular tour season. They each have a theme: landscape, preservation, observation and biography.

The tours started Tuesday and run every day through October.

Copyright 2012. The Associated Press.