STS-98 brought up the Destiny Module and attached it to the forward side of Unity. STS-100 brought up the Canadarm2 - which was crucial for constructing the station.

On Dec. 6, 1998, the station's first two elements- the Unity and Zarya modules-were joined in low Earth orbit." Nasa said while sharing before and after pictures of the International Space Station.

On Dec. 6, 1998, the six-member STS-88 crew mated Unity, the first U.S. element of the International Space Station, with the already-orbiting Zarya module, beginning the historic assembly of the ...