Behind the second curtain was a second section called the Most Holy Place, having the golden altar of incense and the ark of the covenant covered on all sides with gold...
Hebrews 9:3-4

The altar of incense here is used by some skeptics as a "contradiction" in the Bible since the altar of incense was outside the curtain, not behind it. However, this is probably just a problem with translation. "Altar" almost certainly should be "censor". This passage is about Yom Kippur, the only day of the year on which the High Priest goes behind the curtain...with a censor of incense taken from the altar.