Was there anything behind the curtain of the Second Temple?
In the second temple, built by Zerubbabel, and in the more elaborate temple of Herod, there was no Ark in the Most Holy. At the time of Jesus' death, the curtain that separated the Holy from the Most Holy was ripped in two, so the priests carrying their work in the Holy place could see that there was no Ark. The Ark represented God's presence with them.
Jeremiah foretold a time when the ark of the covenant would be no more, but that it would not be missed and God's worshipers would experience no hardship because of not having it. Instead, Jerusalem itself will be called the throne of Jehovah.
Jeremiah 3:16-17 (NASB)
16 And it shall be in those days when you become numerous and are fruitful in the land,” declares the Lord, “they will no longer say, ‘The ark of the covenant of the Lord.’ And it will not come to mind, nor will they remember it, nor miss it, nor will it be made again. 17 At that time they will call Jerusalem ‘The Throne of the Lord,’ and all the nations will assemble at it, at Jerusalem, for the name of the Lord; and they will no longer follow the stubbornness of their evil heart.