There's an excellent bookstore on the ground floor of the Singer building. The upper floors house the Vkontakte offices (which I didn't know before/as I just found out/previously unbeknownst to me).

There's an excellent bookstore on the ground floor of the Singer building, with the Vkontakte headquarters (which I didn't know before/as I just found out/previously unbeknownst to me) located on the upper floors.