NEW YORK -- The Ted Koppel era on ABC's "Nightline" ends with his farewell Tuesday night after 25 years of offering a serious alternative to late-night laughs.

Koppel's final broadcast was to be a look back at one of his favorite interviews: his 1995 conversation with terminally ill college professor Morrie Schwartz, which led to Mitch Albom's best-selling book "Tuesdays with Morrie."

"Nightline" will continue Monday with a revamped format and hosts Martin Bashir, Cynthia McFadden and Terry Moran.

The program officially began in March 1980. After Koppel spent several months briefing viewers each night about the Iranian hostage crisis, ABC put him in that time slot permanently.

Koppel's live interviews were the early drawing card. At the time, with CNN just starting as the only all-news network, it was a novel idea to bring interview subjects together from all over the world.

His voice rarely rose -- and the famous helmet of hair stayed in place -- but Koppel's incisive interviews continued through Hurricane Katrina and his memorable takedown of former Federal Emergency Management Director Michael Brown.

"Our legacy," Koppel told the Associated Press, "is that a serious news broadcast can be successful on all counts, without catering to anyone's baser instincts. 'Nightline' has made a lot of money. It has been successful in terms of viewership, awards and accolades. But most important to me, it's been successful in not ever having to lower its standards."