国际英语新闻：Germany celebrates 20 years of unification as Wulff calls for "new unity"

In the beginning of the ceremony, guests were surprised at hearing greetings from outer space. U.S. astronaut Doug Wheelock and his colleagues sent best wishes to Germany from the International Space Station (ISS), the largest internationally- developed artificial satellite that has ever orbited the Earth.

Congratulations also came from U.S. President Barack Obama and his Russian counterpart Dmitry Medvedev, whose country represented two victorious powers and divided the defeated Germany into four parts with Britain and France in 1940s.

Wulff delivered his first major speech since taking office in June during the ceremony, which was eagerly awaited by the public and media.

He told East Germans: "You have done it, with an incredible willingness to change," adding that "it was East Germans who shouldered the vast majority of changes so that our country could be united again ... This has not been appreciated sufficiently."

The president then changed his focus on "what does a united Germany means today" and shared his thoughts on a recently disputed topic -- immigration and integration, an issue triggered by German Central Bank board member Thilo Sarrazin's disparaging remarks on Muslim and Jewish immigrants. Wulff said earlier that he viewed as integration of the society as "a priority" in his term.

"Twenty years after unification, we are facing a huge task of finding new cohesion in Germany in the rapidly changing world," he said. "We are one people! This slogan of the unification must now be an invitation to all who live here."