For a master bathroom renovation in a space inspired by Spain and the warm, inviting aesthetics of cinnamon hues, you could consider the following design elements to create a luxurious, functional, and beautiful space:

1. Warm Color Palette
Earthy Cinnamon Tones: Use shades of cinnamon, terracotta, and beige for walls or tiles to bring warmth and elegance. This creates a cozy, inviting atmosphere reminiscent of Spanish interiors.
Accent Colors: Pair warm tones with neutral shades like ivory, cream, or even muted greens to balance the earthy colors and add a sophisticated contrast.
2. Spanish-Inspired Tiles
Mosaic or Moroccan Tiles: Incorporate decorative tiles in intricate patterns on the floor or as a backsplash. Spanish or Moroccan tile designs add a distinctive Mediterranean vibe.
Terracotta or Stone Tiles: Use larger terracotta tiles or stone for the flooring, enhancing the rustic Spanish charm and adding warmth underfoot.
3. Luxurious Bathtub and Shower Combo
Freestanding Tub: A statement tub in a rounded or slipper style brings a vintage feel. For a rustic touch, consider a tub with a bronze or copper finish.
Walk-In Shower with Frameless Glass: A walk-in shower with frameless glass creates an open, spacious feel. Use textured tiles for the shower wall to add visual interest.
4. Wooden and Wrought Iron Details
Natural Wood Elements: Introduce wood through vanities or cabinetry in rich tones like walnut or oak to create a warm, rustic feel.
Wrought Iron Fixtures: Spanish design often incorporates wrought iron, so consider using it for mirror frames, towel racks, or lighting fixtures.
5. Arched Details
Arched Doorways or Mirrors: Spanish architecture often features arches, which you could incorporate through arched mirrors, shower niches, or doorways.
Built-In Arched Shelving: Create built-in shelves with an arched top for storing towels or décor, adding both functionality and style.
6. Stone Sink and Countertop
Natural Stone Sink: Opt for a stone sink in a light, natural shade for a rustic yet refined look that complements the warm color palette.
Marble or Stone Countertops: Marble with subtle veining or a stone countertop adds elegance to the space and pairs well with the cinnamon tones.
7. Accent Lighting and Décor
Pendant or Lantern Lighting: Use lantern-style lighting or metal pendant lights with intricate cutouts, adding soft ambient lighting that enhances the warm tones.
Decorative Accents: Add Spanish-inspired pottery, small plants, or woven baskets as decorative accents for an added touch of character and authenticity.