I would create a great temple in the desert. There would be statues and paintings of various ancient Mesopotamian and Abrahamic gods and goddesses, with epic depictions of Celestial and Infernal beings- such as archangels and archdemons- and glorious portrayals of the Hells and Heavens as well as the Earth and the cosmos. There would be all kinds of astrological alignments in the architecture and events that only occur on Soltices and Equinoxes. There people would go to worship Ashtoreth, Lilith, Michael, Lucifer, Abzu, Tiamat, YHWH, and many others. Especially YHWH.
I would have it so that to access this temple one would have to journey deep into the desert to reach it. There would be an underground river far beneath the temple complex, with caverns leading to mysterious places and subterranean chambers of worship.
Most of the temple would be built of stone. Above ground, certain chambers of the temple would have wide open unroofed areas of worship to allow the sun within during day, and to observe the Moon, stars and planets at night. One such area would look like an arena of sorts, with an elevated area in the center to allow for physical training or various spiritual-religious events, such as ceremonies and sacrifices.
On some nights, attendents would have the chambers and halls beautifully lit up with torches, though on other nights there would be only darkness, so as to observe the night sky with the greatest clarity. Around the complex would be like a desert oasis, with ponds and springs and palm trees... and the wide open areas in the temple would be no different.
The temple would be beautiful.