She started sleeping all night (as in 10 to 12 hours) about 11 days before her eight month birthday. That lasted for about three weeks, and then she reverted back to waking up every three hours. After about a week of that, we just let her cry it out. That took about three nights and now she's back to sleeping all night again.
We discovered that she has a small birthmark on her left arm, right above the elbow.
Nine month comparison pictures.