Scenic places to visit around midnight (mall, park, distance)

[prathyusha]

I am planning to have a small cake cutting thing for my husband somewhere outdoors in DC at midnight. Are there any places where I can have a good view of the Potomac River around midnight?
Or even some scenic places other than the national mall area, where I can spend an hour or so around midnight?

I found this place called Gravelly Point Park where we could see planes at a close distance. But the park hours say until 10 pm. Can I still walk about around midnight?

Please let me know.

[Fundman]

Not sure what a small cake cutting means but the Lincoln Memorial is open 24 hours a day.