Introduction:
Cathedrals are monumental structures that played a significant role in medieval Europe. They served as places of worship, symbols of power and authority, and centers of cultural and artistic expression. The design features of cathedrals evolved over time, reflecting advancements in architectural techniques and changing religious beliefs.

1. Gothic Architecture:
- One of the most prominent design features of cathedrals during the medieval period was Gothic architecture.
- Gothic architecture is characterized by pointed arches, ribbed vaults, and flying buttresses.
- These architectural elements allowed for greater height and spaciousness in the interior of the cathedrals.
- The use of pointed arches distributed the weight of the structure more effectively, allowing for taller walls and larger windows.
- Ribbed vaults provided structural support and allowed for more intricate and decorative ceilings.
- Flying buttresses were external supports that helped counteract the outward thrust of the vaults, allowing for thinner walls and larger windows.

2. Stained Glass Windows:
- Stained glass windows were another prominent design feature of cathedrals.
- These windows were made of colored glass arranged in intricate patterns and designs.
- Stained glass windows served as a means of conveying religious narratives and teachings to illiterate worshipers.
- The use of vibrant colors and light streaming through the windows created a celestial and ethereal atmosphere within the cathedrals.

3. Sculptures and Carvings:
- Cathedrals were adorned with numerous sculptures and carvings, both inside and outside.
- Sculptures depicted biblical scenes, saints, and other religious figures.
- Carvings adorned the doorways, columns, and other architectural elements of the cathedrals.
- These sculptures and carvings served as visual representations of the religious stories and teachings.

4. Rose Windows:
- Rose windows were large circular windows with intricate tracery patterns.
- These windows were often placed on the facades or transepts of the cathedrals.
- Rose windows served as decorative features and allowed light to enter the interior.
- The intricate tracery patterns added a sense of delicacy and beauty to the overall design.

5. Towers and Spires:
- Cathedrals often featured tall towers and spires that reached great heights.
- Towers served as symbols of the church's power and authority.
- Spires added a vertical element to the overall design and created a sense of aspiration towards the divine.

Conclusion:
The design features of cathedrals during the medieval period were characterized by Gothic architecture, stained glass windows, sculptures and carvings, rose windows, and towers and spires. These features not only served functional purposes but also conveyed religious narratives and created a sense of awe and inspiration among worshipers. The design of cathedrals reflected the religious and cultural values of the time and continues to be admired for its architectural and artistic achievements.