Last week in Washington, D.C., a public congressional hearing on UFOs was held for the first time as fears grew over threats to air travel and national security posed by "unknown technology."

It also looked into the possible cover-up of government-funded programs to recover and investigate flying objects of a non-human origin.

To mark the occasion, the curator of the "A UFO in 1665" exhibition in Berlin's Kunstbibliothek invited guests for a free visit last weekend to exchange ideas on the topic of uninvited extraterrestrials.

The title stems from the first known reports of a UFO in Germany some 350-odd years ago. On April 8 that year, "six fishermen witnessed an unexplained celestial phenomenon — an aerial battle in the skies above the Baltic Sea near Stralsund," remarks the National Museums in Berlin website.

UFOs have long been a central theme in popular culture. TV shows and films from "Mork and Mindy" to the "X-Files," from "E.T." to "Men In Black," and music bands from the Carpenters to Radiohead, have played with the notion we may not be alone in the universe.

DW takes a look at culture that embraced the idea of extraterrestrials and imagined their interactions with the human race.

'Mork and Mindy': One of the first

Mork, played by the late Robin Williams, an alien from the planet Ork on a mission to Earth to study human behavior, traveled to 1970s Boulder, Colorado, where he meets up with Mindy, played by Pamela Dawber, a young journalism graduate.

While trying to get a grip with life on Earth and greeting everyone with a "Na-nu, na-nu," Mork falls in love with Mindy. They eventually marry and have a son, Mearth from Earth, who ages backwards like his father.

'The X-Files': The truth is out there

David Duchovny and Gillian Anderson shot to fame as Fox Mulder and Dana Scully in the 1990s as they pulled out all the stops as FBI agents investigating inexplicable paranormal cases.

The iconic, mysterious music and footage of unidentified objects in the sky that marked the show's opening saw conspiracy theorist Mulder and realist Scully go in search of unexplained forces in our midst. As the intro built to a crescendo, the iconic words would hit the screen: "The truth is out there."

E.T. went home

"E.T. the Extra-Terrestrial" (or simply E.T.) is an American science fiction film from the 1982 produced and directed by the legendary Steven Spielberg and written by Melissa Mathison.

After a gentle alien becomes stranded on Earth, the being is discovered and befriended by a young boy named Elliott, played by Henry Thomas. Bringing the extraterrestrial into his suburban California house, Elliott introduces E.T. to his brother and his little sister, Gertie, played by Drew Barrymore, and the children decide to keep its existence a secret after building an emotional bond. Soon, however, their alien friend falls ill, resulting in government intervention and a dire situation for both Elliott and the alien.

E.T does recover, however, and with some assistance is helped to find his way home.

The movie was an instant hit and cemented Spielberg's reputation as one of Hollywood's best filmmakers.

'Men in Black': First, last, and only line of defense

"Men in Black," starring Will Smith and Tommy Lee Jones, is a series of American science-fiction action comedy, based on Marvel comics.

Working for a highly funded yet unofficial government agency, Kay and Jay provide immigration services and regulators of all things alien on Earth. While investigating a series of close encounters, the agents uncover the deadly plot of an intergalactic terror agent who is plotting to assassinate two ambassadors from opposing galaxies currently residing in New York City.

Lee Jones, however, was not the first choice as Smith's humorless mentor, with the studio preferring Clint Eastwood for the role.

The first version of the movie, released in 1997, was another success for Smith's burgeoning Hollywood career, which not only garnered nearly $600 million (€550 million) at the box office, but was also one of the best-reviewed films of the year. 

Radiohead: OK aliens

British band Radiohead, hailing from the leafy Oxfordshire town of Abingdon, had already conquered the rock scene by the time the album "OK Computer" was released in 1997.

But this album catapulted them into a new stratosphere, including the track "Subterranean Homesick Alien," a song about an individual that dreams of being abducted by aliens in order to escape the misery of his life on earth. Some say the song is literally about visitors from outer space.

Meanwhile, Radiohead singer-songwriter Thom Yorke said the song was a tribute to Bob Dylan's "Subterranean Homesick Blues."

The Carpenters: 'Calling Occupants of Interplanetary Craft'

Although the song was originally released in 1976 by Canadian band Klaatu, the Carpenters' version a year later gained more prominence thanks largely to Karen Carpenter's fine vocal performance.

"Calling Occupants of Interplanetary Craft" urges its listeners to use the combined power of their minds to enable them to contact the "occupants of interplanetary space," claiming in the opening line that "In your mind you have capacities you know, to telepath messages through the vast unknown."

But the song has a happy ending, concluding that "we are your friends." 

The song has endured and featured in a 2011 episode of the BBC's "Wonders of the Solar System," presented by Professor Brian Cox.

Edited by: Stuart Braun