The jet age in civil aviation began with Boeing 707 and DC-8. It was Boeings break-through in civil aviation sector and the trans-atlantic air business was made possible. Actually, the 707 (or Dash 80) was developed as a tanker for USAF, but the prototype Boeing 367-80 was developed further for civil aviation, even if Boeing was nearly ruined by the immense costs of development.
The first flight of the Boeing 707 was in 1954, one year later Pan Am caused the starting signal for the civil version. This legendary airline got its first Boeing 707 in December 1957 and nearly one year later a trans-atlantic route to Paris was launched with Boeing 707-120. In 1959 the prototype of the most popular version Boeing 707-320 left the hangars, whose range caused the real break-through on the market. Launching customer was Pan Am again, the transcontinental version -420 was delivered to Lufthansa one year later.
To have a 707 for shorter routes, too, the Boeing 720 was built, a Boeing 707 with shortened fuselage and less range. 154 ones were built. In 1963 the last versions 707-320B and C were presented. The C-Versions have a cargo door at the side of the fuselage, to be also available for cargo flights. Nowadays it is the most common version of the 707's left.
The last Boeing 707, a 320C, left the hangars of Boeing in 1978, the military version was built until 1991. Altogether 855 Boeing 707's were built. Nowadays it's difficult to see a 707 still in service, probably you'll find some in military service ( a good example are the AWACS-707 of the USAF). But the civil versions are -thanks to strict noise restrictions- widely banned from the airports of Northern America and Europe. Especially in Africa you can see still 707 in cargo service. But there are nearly no passenger versions left nowadays, the largest passenger 707 airline at last, MEA from Lebanon, has long since retired its 707 fleet.