Noticeable, remarkable, prominent, outstanding, conspicuous, salient, signal, striking, arresting can all mean attracting or compelling notice or attention.
Noticeable implies that the thing so described is unlikely to escape observation.
Remarkable adds to noticeable the further implication of inviting comment or of demanding a call to others' attention; it commonly imputes to the thing so described an extraordinary or exceptional character.
Prominent seldom loses its basic implication of protuberance or projection above a level or beyond a surface; it is applied appropriately to things that noticeably protrude from their background.
In extended use it is applied to persons or things that stand out so clearly from their surroundings that they are often in evidence, are generally known or recognized, or are frequently pointed out; in such use it typically attributes superiority or importance to what it describes.
Outstanding, although it implies prominence, is applicable only to what rises above or beyond others of the same kind and is remarkable by comparison with them.
Conspicuous is applicable chiefly to what is so obvious or patent that the eye or the mind cannot miss it. It is also used to describe what strikes the eye or the mind, often unpleasantly, through its singularity.
Salient stresses emphatic quality and is applied to what demands the attention or impresses itself insistently upon the mind; it imputes significance more often than obtrusiveness to the thing so described.
Signal suggests such distinction from what is ordinary or usual that the thing so described is in itself remarkable or memorable.
Striking is applicable to what impresses itself powerfully and deeply upon the observer's mind or vision.
Arresting adds to striking the suggestion of capturing attention or of being of more than passing interest.