Well if you need lots of Leds for something like this then Ghurd is the one to see.
He has great quality Leds that will last a long long time and use low power, just like Leds should. Provided you do the wiring correct for your use.
With a landmark you don't want and can't afford the cheap China made LEDS that will blow one out and then fry a whole string, people will look and say what crap!
You need High QUALITY LEDs that will last and make your landmark something people will say WOW, Ohhh, Aughhh, about and then tell their friends who will come look and then tell their friends Ect..
You need High quality stuff people will think is worth looking at! Not allot of blowed out fried cheap China stuff. See Ghurd for Quality Leds that work!