落成 らくせい しき
rakuseishiki

Noun

1. ceremony to celebrate the completion of a building; inauguration ceremony

わたくし たちはそのビルの落成 らくせい しき出席 しゅっせきしました。
watashitachiwa sono biruno rakusēshikini shusseki shimashita
We were present at the dedication ceremony of the building.