The ceremony was quiet and brief. At about noon, a procession of diplomats and private mourners made their way from the Spanish Embassy to Washington Circle. Once there, Spanish officials stood silently behind the white placards for about five minutes. They then dispersed and the media converged on the white-haired gentleman, who a reporter told me was the Spanish Ambassador. His voice broke and his eyes misted as he spoke briefly in Spanish and then English, and the key quote was:

"The Spanish people, along with the American people, all the freedom-loving peoples of the world - we will persevere together." (It was difficult to hear him, but I'm 99% sure this is accurate).

The ceremony then slowly dispersed, with the crowd mingling around the circle and the embassy, where flowers and tokens were continuously being dropped off. DC Police had one side of Penn Avenue blocked off and the crowd was riddled with various security personnel. I'm horrible at estimating crowds, but I'd say a couple of hundred people were there.

UPDATE:

Another ceremony: Bush Expresses Condolences to Spanish Ambassador