Built in 1534, sacked and burned by Henry Morgan in 1670, then rebuilt, the church itself is pretty, but ascend the tight spiral stairs of the bell tower (open 10 a.m.–6 p.m. daily, $1 entrance fee) for the single most spectacular view in Granada [1].
Look over an ocean of tiled roofs to the lake and isletas [2], with Volcán Mombacho [3] over your shoulder. The scene changes over the course of the day; late afternoons are best when the shadows are long.
Links:
[1] http://www.moon.com/destinations/nicaragua/granada
[2] http://www.moon.com/destinations/nicaragua/granada/near-granada/las-isletas
[3] http://www.moon.com/destinations/nicaragua/granada/near-granada/volcan-mombacho