This paper reports about our efforts in creating a tri-lingual parallel treebank. The focal points are consistency checking and all aspects of sub-sentential alignment. We discuss the alignment guidelines, the importance of quality checks, and special alignment problems. Then we look at alignment algorithms and alignment visualization tools and we compare our own TreeAligner with other alignment tools. Our constituent structure treebanks contain just over 1,000 sentences and around 18,000 tokens in each language.