A theming bonus is a Tourism and Culture bonus acquired by combining Great Works according to certain requirements in most cultural World Wonders and Museums. The Culture bonus from theming is added to the city's base Culture (which is affected by Culture bonuses from buildings such as Hotels and Airports); the Tourism bonus applies directly to the total city output.
Checking your theming bonus
Go to the Culture Overview screen, open the tab "Your Culture". In buildings and wonders that have more than one slot for a Great Work (e.g., any Museum, the Great Library, the Louvre, etc.) you will see a +0 next to the Great Works in that building. Mouse over the +0 to see what you need to do to activate the theming bonus for this building or wonder. If the theming bonus is activated, you will see a number instead (e.g. +1, +2).
Theming bonus details
There are a total of nine Wonders and one building with theming bonuses in Civilization V.
|Building||Icon||Theming bonus||Theming requirements|
|Great Library||2||Fill the slots with Great Works of Writing from different civilizations and different eras.|
|Sistine Chapel||2||Fill the slots with Great Works of Art from the same civilization and the same era.|
|Globe Theatre||2||Fill the slots with Great Works of Writing from the same civilization and the same era.|
|Uffizi||3||Fill the slots with Great Works of Art from the same civilization and the same era.|
|Louvre||4||Fill the slots with 2 Great Works of Art and 2 Artifacts from different civilizations and different eras.|
|Broadway||3||Fill the slots with Great Works of Music from the same civilization and the same era.|
|Sydney Opera House||2||Fill the slots with Great Works of Music from the same civilization and different eras.|
|Oxford University||2||Fill the slots with Great Works of Writing from other civilizations and different eras.|
|Hermitage||3||Fill the slots with Great Works of Art from different civilizations and different eras.|
|Museum||1 or 2||Fill the slots entirely with either Great Works of Art or Artifacts, both from your civilization or both from one or two civilizations other than you, and from the same era. If you only fulfill 2 requirements, it provides +1 theming bonus.|
It is important to acquire as many Great Works as possible for a cultural victory. Set up a high population city (usually your Capital) with a lot of buildings and wonders that speed up Great Person generation. It is more efficient to house all the Guilds in one city because most of the Wonders that increase Great Person generation only have city-based bonuses. Use the World Congress to increase cultural Great Person generation, through the Arts Funding resolution.
Plan your Great Person generation depending on the wonders you are planning to get. Early game wonders focus on writing, mid game wonders on art and late game wonders on music. This is especially important with wonders that require multiple Great Works from the same era. You can delay going to the next era by changing your research until your last Great Person needed for the theming bonus spawns. You can also save Great People for an immediate theming bonus when you complete a late game wonder, because the Great Work era is determined by the era when it was created, not when the Great Person was generated.
You can use the Great Writers' Political Treatise ability to complete Aesthetics faster and double your theming bonus as early as possible. It will be a greater increase of tourism compared to popping it for another Great Work (unless, of course, you've already completed the tree, in which case a Great Work is better). When you fill all your Wonders with Great Works of Art, and if your archaeology is strong, use your Great Artists for Golden Ages instead of Great Works. The reason for this is that Museum bonuses can be fulfilled with Artifacts as well, and they are the only other building with Art slots. This is doubly valid if you're playing as Brazil, whose special ability doubles Tourism during Golden Ages.