I'm primarily something up in space, But Mars named a chocolate after me, They call me Dove in America, But in the UK I am...

A word for the best tales and the mountain heights

I'm the place you want to be If you're picnicking at the park. I'm covered but not enclosed Please leave before it's dark. There tables to be rented Under me you'll be tented. Keep my area clean for the next family There's plenty of room to share happily.

I host iron guests that cannot swim, Their bellies scarred, their futures dim. I drain the deep but keep the hull, Where rust and paint wage wars in full. I’m land and sea in measured blocks, A resting place that mends their shocks.

I circle a castle but I'm not a wall, I hold back the enemy, yet let no stone fall. Fill me with water and I'll keep you afloat. What am I?