A fantastic ending to a wonderful series. Rick Riordan is an amazing storyteller. This last book in the series (Heroe's of Olympus/Percy Jackson) is a fitting tribute to all the characters.
I am sad to see the series end. I've come to know Percy, Jason, Annabeth, Piper, Nico, Frank, Hazel and Leo as friends. I hope there will be more in the future. Even though the series is over, would be great to have more adventures with these guys!