Halcyon House is an amazing venue sitting directly above the Potomac River overlooking Rosslyn in the heart of Georgetown. As a private residence and restored 18th-century mansion, it is amazingly open for guests to enjoy. Gorgeous views and 20-30' ceilings provide a wonderful atmosphere for a reception, and John Dreyfuss' studio, carved out of the hillside, allows for hundreds of guests for dinner and dancing. Wendy Charles, the Executive Director for the house was great, totally accommodating to the rest of the vendors, and making sure that we had access to the house whenever we needed. The only caveat to this amazing location: the cost, ranging into the five figures. But for a once-in-a-lifetime event, you couldn't ask for a better spot.