It seems to me that the beauty of HaShem's world is this: On Har Sinai, the whole world spoke up and told us that HaShem is One. From that time on, it is our job to give voice to the whole world, to unite HaShem's name in the world and proclaim HaShem's One-ness in the name of all the world.
How is it that we can give voice to the world? The Talmud explains that mankind is called the challah of the world. Challah is a special offering, a small quantity of any dough that is prepared is given to the Kohanim and is attributed Holiness, Kedushah. In a way this is similar to the kedushah of other such tithes, ma'aser or terumah, or even the first fruits and first born. What it means is that mankind represents the microcosm of the macrocosm.
Another midrash describes a similar idea by saying that in order to create Adam, the first man, HaShem gathered dust from the four corners of the world. Astronomers and science fiction writers take great pleasure in pointing out that most of the heavier elements that make up the world around us, including our bodies are elements that were forged in the hearts of stars in the early universe. I don't think they've ever equated these two ideas from these two vastly different frames of mind. Adam's body [and soul too] was created from a gathering of a little bit of everything created.
There are other midrashim that hint at the same idea, one example equating different parts of the human body with different animals, etc. Other parshanim explain (as we've mentioned in the past) that the Mishkan was a microcosm of both the world, and the human body, implying that the human body is a microcosm of the world. The Tikkunei Zohar goes into this in depth, explaining the metaphor pertaining to the various major organs.
In short, we here today, each one of us, is a microcosm, gathered from the furthest reaches of space and time, heaven and earth. We are the true testament to HaShem's Oneness. If HaShem wasn't One, how could a little bit of everything created be brought together into a single creation.
On Har Sinai the whole world proclaimed it for us, just to bring the point home. Today, it is our job every time we say Shema Yisrael, (2 (3*1) times a day) to embody the whole world, as its representatives.
HaShem Elokeinu HaShem Echad - Hear O Israel, HaShem created and sustains everything in creation, HaShem is One.
The whole world waits every morning and every evening to hear us proclaim this deepest truth, to fulfill its deepest purpose, to bear witness to the oneness of HaShem.*2
This is also a good kavanah to have when you recite Perek Shirah, that all the animals of the world are waiting to praise HaShem, but they need you to give voice to their prayers.
*1 We say Shema Yisrael in the morning and evening prayers, and we are meant to repeat it (a third time) on our bed every night before we sleep.
*2 The Ramhal in his Da'ath Tevunoth explains that the whole purpose of creation is to make us aware that HaShem is One.