Most often, cake makers choose the vertical route: Tall wedding cakes are the rule rather than the exception in most parts of the world. Consider both the three-tiered wedding cake served at a small backyard wedding in the United States and the teetering croquembouche served at a French provincial wedding. Like cathedrals and skyscrapers, tall cakes reach for the sky, toward the infinite, toward heaven. While horizontal cakes can be as beautiful as any skyscraper, the tall cake is grander, and more easily visible to every guest, staking its claim to a dominant place at the party. Tall cakes, however, pose a number of challenges to cake designers. Like architects, cake makers have to balance the horizontal and the vertical to achieve a good-looking edifice.
Tall cakes run into the same laws of physics as tall buildings: If they're built too high, and the weight isn't evenly distributed, the cake may either cant like the Tower of Pisa, or, worse, collapse altogether. British wedding cakes are traditionally made of dense fruitcake reinforced on the outside with layers of marzipan and hard icing. The overall mass of cake becomes so solid that the upper layers cannot sink into the lower layers. The consequence of all this, though, is that not only will the icing not give way under the weight of the higher tiers, it will sometimes not give way under the cake knife, a source of many nostalgic anecdotes in the United Kingdom.
In addition to elements of proportion and structure, architectural-decorating styles have influenced the designs of wedding cakes. Historically, buildings have been bare stone or wood surfaces embellished with applied ornaments, like friezes, pilasters, and pediments, the design of which are easily adapted to wedding cakes. Components of Greco-Roman architecture, for example, invoke a sense of classical style, but on wedding cakes, their use must be tempered by restraint -- the effect should be reminiscent of ancient Rome, not contemporary Las Vegas.
As with everything else in the wedding celebration, the cake presents an opportunity for the bride and groom to express themselves creatively. Even lovers of simplicity and modern style might find themselves falling for elaborate cakes, just as they might occasionally cast an admiring glance at a building so lavishly decorated as to earn the description of "wedding cake architecture." Sullivan, the architect who was famous for the expression "Form ever follows function," and whose sensibility established him as the father of modern American architecture, nevertheless decorated his own buildings extravagantly. With his appreciation for elegance of form, the importance of function, and the appeal of ornament, Sullivan would have indeed made a top-notch wedding cake designer.