1954: WHYY-FM begins operations in Philadelphia, broadcasting 25 hours of programming each week, with a yearly budget of $50,000.

1957: WHYY-TV signs on with a UHF signal as Channel 35, an educational station broadcasting instructional programs for the School District of Philadelphia to classrooms, from 9 to 3. Its call letters are acronyms for "Wider Horizons for You and Yours."

1963: WHYY-TV signs on as TV12, licensed to Wilmington, DE, with a VHF signal of 316,000 watts. WHYY retains its offices in Philadelphia and opens a second studio in Wilmington in a vacant red school house.

1965: WHYY-TV is the first public station in the U.S. to broadcast in color. Walter Annenberg donates studios in West Philadelphia, the former home of American Bandstand.

1966: Julia Child as The French Chef bursts into viewers' homes on TV12 in the first how-to cooking show on television.

1967: President Johnson signs the Public Broadcasting Act, establishing the Corporation for Public Broadcasting (CPB) to provide funds to support public broadcasting, and WHYY helps establish the Pennsylvania Public Television Network, a statewide consortium of public television stations.

1968: Mister Rogers moves into his neighborhood on TV12.

1969: Big Bird steps onto Sesame Street and Louis Rukeyeser onto Wall Street. The Forsyte Saga captivates TV12 viewers.

1970: The Public Broadcasting Service (PBS), established by an act of Congress as a program distribution service, begins operations, and WHYY joins 195 other stations as PBS affiliates. National Public Radio (NPR) is incorporated.

1971: TV12's transmitter is moved from Glassboro, NJ to the "antenna farm" in Roxborough, PA, expanding the broadcast signal. National Public Radio (NPR) launches its first live nationwide broadcast with coverage of the Senate Hearings on Vietnam. All Things Considered, created by Bill Siemering, debuts, and the curtain rises on Masterpiece Theatre on TV12.

1973: TV12 and 91FM carry gavel-to-gavel coverage of The Watergate Hearings, the longest broadcast coverage ever devoted to one news event. PBS pioneers closed captioning of television programs for the hearing impaired.

1974: Great Performances bows on TV12, as NOVA opens up new scientific frontiers.

1975: Fresh Air with Terry Gross debuts on 91FM as a local daily radio program, and the Robert MacNeil Report, forerunner of The MacNeil/Lehrer NewsHour, begins on TV12.

1977: Luciano Pavarotti brings opera to millions of homes with the premiere telecast of The Metropolitan Opera Presents.

1978: WHYY leases from the city of Philadelphia for $1 a year the Living History Center on Independence Mall, a former museum built for the Bicentennial. PBS launches broadcast television's first satellite connection system linking all PBS stations nationwide.

1979: Morning Edition brews its first reports on 91FM. Mystery! and This Old House debut on TV12.

1980: Public television pioneers the development of multichannel ("Stereo") TV broadcasting, and A Prairie Home Companion comes to 91FM from Lake Wobegone.

1983: Frontline and Reading Rainbow take center stage on TV12. WUHY-FM reverts to its original call letters, WHYY-FM. TV12 produces its first live broadcast from Dover, DE with a satellite telecast from Legislative Hall.

1984: WHYY's signature Spotlight series makes a grand entrance on TV12.

1985: National Public Radio's Weekend Edition is first heard on 91FM.

1986: TV12 and 91FM simulcast live 144 hours of the Move Commission Hearings, earning praise for community service. WHYY assumes operation of WDPB, Channel 64, in Seaford, DE, expanding TV12's service to southern Delaware. WHYY-TV teams with Dean Johnson as co-producer of Hometime, a national how-to, do-it-yourself series.

1987: WHYY-FM's Fresh Air with Terry Gross debuts as a national daily program, and Radio Times with Marty Moss-Coane joins the 91FM lineup.

1988: Congress authorizes $200 million to replace public radio and TV satellites.

1990: Ken Burns' moving documentary series, The Civil War, attracts the largest ever audience to public television. WHYY's state-of-the-art Delaware Operations Center opens in Wilmington after a successful $3.31 million capital campaign. Descriptive Video Services (DVS) for the visually impaired begins on TV12.

1991: The Three Tenors captivate Delaware Valley audiences on TV12, and The Dinosaurs!, a WHYY-produced national series, is the one of most-watched TV12 programs in station history.

1992: Washington Week in Review, public television's longest-running public affairs program, celebrates its 25th anniversary.

1993: Things That Aren't There Any More launches WHYY's nostalgia series.

1994: WHYY's Ready To Learn service, on TV12 and in day-care centers, prepares young children for school.

1995: WHYY forms Delaware Valley Distance Learning Consortium, an alliance of 47 colleges and universities, and WHYY initiates its in-service Mathline training for middle-school teachers in Delaware.

1996: WHYY Home College Service is the biggest start-up provider of distance learning for adults in the PBS system, and WHYY teams with Philadelphia schools in Strawberry Mansion and at Edison High School to bring technology into classrooms. Les Miserables: The Tenth Anniversary Concert is the most successful fundraising program ever broadcast on TV12.

1997: WHYY forms its Educational Services Department. William J. Marrazzo joins WHYY as the station's fifth chief executive officer.

1998: Classical 24, WHYY's 24-hour classical music service, debuts on TV12's second audio program (SAP) channel.

1998: WHYY breaks ground for a new Technology Center in Philadelphia on Independence Mall.