Which word best describes something that is remarkably grand and likely to inspire admiration?

The word "sublime" is the best choice to describe something that is remarkably grand and likely to inspire admiration. It conveys a sense of overwhelming beauty or grandeur that elevates an experience or object beyond the ordinary, often inspiring deep appreciation or awe in those who encounter it. The term "sublime" is often used in art, nature, and literature to denote qualities that are elevated and extraordinary, evoking a strong emotional reaction.

In contrast, the other words do not carry the same connotation of grandeur or admiration. "Subdued" refers to something that is quiet, restrained, or softened, which lacks the grandeur implied in the question. "Substandard" indicates something that does not meet quality standards, which is the opposite of inspiring admiration. Lastly, "subtle" describes something that is delicate or understated, which might not evoke the sense of grandiosity needed to inspire admiration in a significant way. Thus, "sublime" is the most fitting term in this context.