[QUICK THREAD: AMSTERDAM'S XXX]
1/11
Most European cities date back to the Middle Ages if not Antiquity, and have an imperial coat of arms. This one's Amsterdam's. What you see in the middle column are not 3 letters but 3 crosses, Saint Andrew's Crosses or saltiers to be precise.

2/11
The reason St. Andrew's Cross looks like that is because the saint was martyred on an X-shaped cross, instead of the more familiar + kind. He was one of the apostles of early Christianity and was crucified by the Romans for heresy.

3/11
The reason this particular cross features on the city's coat of arms is because the apostle in question was a fisherman. And Amsterdam was founded as a fishing village back in 1505. St. Andrew is the most natural patron saint of fishermen around the world.

4/11
Being the official municipal herald, this coat of arms appears all over Amsterdam. Take the city hall building (officially, the Stopera), for instance.

5/11
Or this heritage building, certainly older than 1947 as it didn't include the motto (Heldhaftig, Vastberaden, Barmhartig). The motto was added only in 1947 by Queen Wilhelmina to honor the bravery and compassion shown by the city during the General Strike of 1941.