BETHESDA, Md. - Standing outside the 11-story office building known as Bethesda Place, across the street from a car dealership, you would be hard-pressed to identify this as the home of the Discovery channel, let alone the headquarters of a global TV colossus. Inside, there isn't even a TV studio - just floors and floors overflowing with employees of Discovery Communications Inc. As they like to say around here, the whole world is their studio. And so is their audience. After CNN, the biggest beneficiary of the cable and satellite era has been the networks owned by Discovery Communications, now seen in nearly 130 million homes in 144 countries. Besides the namesake, these are the Learning Channel, Animal Planet and the Travel Channel. This is a place where "version" is used as a verb, as when Michael Quattrone, general manager of the Discovery channel, says, "We took a Japanese documentary and versioned it for the U.S." This week, the Discovery networks are rolling out their most ambitious programming slates ever: more than 1,800 total hours of original programming and more blockbusters like last season's "Titanic Live." Discovery, for instance, will supply coverage of Sen. John Glenn's return to space (Oct. 26), and TLC presents "Vietnam: The Soldiers' Story," a new first-person documentary miniseries featuring Sen. John McCain and others who fought in Vietnam (Oct. 11-13). Discovery If you've had cable a long time, you may recall when the Discovery channel was little more than a hodgepodge of other people's programs. Discovery's founder, John S. Hendricks, spent three years assembling investors willing to take a chance on a documentary network. Discovery launched in 1985 with titles acquired from film libraries around the world. It was cheap and made money, but it was unfocused. "We were like the MTV of documentaries - all docs all the time," says Clark Bunting, a 13-year veteran of Discovery who now manages Animal Planet. "Was there programming flow? No, but we had lots of documentaries." As Discovery stopped living hand-to-mouth, it began making its own programs, and here is where it enjoyed an unusual advantage. State-run broadcasters in other countries - like the BBC, and Japan's NHK - spend good money on documentaries. Discovery formed partnerships to make high-quality programs. Foreign partners helped them stay on a cable-sized budget: An hour on the Discovery channel takes $ 250,000 to $ 1 million to produce, compared with $ 800,000 to $ 2 million for an hour of broadcast TV. "Some countries like the show to be hosted; other countries use different music," Quattrone says. "So much of this is working with people who have similar goals to you, so that the major differences aren't editorial but creative." The kind of programs Discovery offers has also evolved, with fewer "hardware shows" on technology and more that tell stories. "The FBI Files," which premieres at 9 tonight, builds an hour around a single criminal case. Among the specials: a special on humpback whales (Oct. 12); and a report on an archaeological dig last year that uncovered ancient Peruvian mummies (Oct. 19). TLC When it was purchased by Discovery in 1991, TLC's schedule was a mess. Today, TLC's schedule is still a mixed bag. Its acclaimed commercial-free block of children's programming, "Ready, Set, Learn," airs weekday mornings from 5 to 11. The afternoon is filled with shows like "A Wedding Story," "A Baby Story," "Reunion" - what TLC manager John Ford calls "lifestyle documentaries. " But the formula seems to work. TLC is one of the most popular cable networks among young adults. Animal Planet Americans own 64 million cats and 63 million dogs. Based on these numbers, it may not be hard to see why Animal Planet is making its way into tens of millions of homes. Easily the most buzzed-about cable channel this year, Animal Planet has a charm embodied in such shows as "The Pet Shop" (comedian Andy Kindler interviews celebrities and their pets) and "Emergency Vets" ("ER" for critters). Travel Channel Having acquired the Travel Channel in December, Discovery rolls out a new lineup this week that better reflects the company's emphasis on storytelling and introduces the first nightly newscast - well, news-related program, at least - on any Discovery network. "Travel Daily," which debuted at 8 p.m. Monday, teams South African Michelle Garforth and "Today" show travel editor Peter Greenberg in a show Travel Channel manager Jay Feldman says will be "like the 'Today' show, only it's all about travel. " The hourlong "Travel Daily" will feature news on new travel destinations and money-saving tips. The rest of Travel Channel's nightly prime-time lineup include new episodes of "Lonely Planet" (7 p.m.), the English un-travel show that will visit Iran and Indonesia, among other locales, this fall; and "Amazing Destinations" (9 p.m.), an exotic anthology series.