Packing ingredients between slices of bread is a universal art the world over. Sandwiches give us an insight into a destination's cuisine, often representing the key flavors of a country.

Sandwiches can be some of the best dishes a country has to offer. They’re honest, substantial, reliable and affordable. In honour of the humble sandwich, we explore some of the world’s top creations.

Greece's souvlaki and Turkey's kebabs are well known, but the Lebanese shawarma deserves more attention. Two thin pita breads are filled with the spiced meat – usually beef, lamb, or chicken.

A combination of two meats is often available, too. The meats are marinated in Middle Eastern spices such as clove, cardamom, cinnamon and sumac before being stacked on a vertical rotisserie.

Shavings of meat are placed onto the pita, complemented by staples such as tabbouleh, pickled turnips, cabbage, lettuce, tomato and onion.

Then come the condiments, often hummus, sometimes toum (Lebanese garlic sauce), tahini and chili sauce. It's all wrapped up and served as is, or toasted to crisp up the bread.

In Portugal's second city, Porto, it’s impossible not to discover the francesinha – an overly-indulgent sandwich guaranteed to scare the health conscious.

The famed sandwich is a layered affair, with pork meat, sausage, bacon, and a beef patty or steak cradled in two slices of thick white bread.

A slice of cheese then crowns the sandwich. But it’s not over: the francesinha is often topped with a fried egg, causing the cheese to melt and fall over the sandwich’s edges.

To finish the elaborate meal off, everything is drenched in a slightly acidic red sauce, combining beer and tomato. Some people add port to the sauce too for some extra kick.

In the speedy stand-up cafes, gas station diners, train station cafes and on the streets, tramezzini are always ready. The charming, triangular, crustless sandwiches are small, but tasty.

A section of the sandwich reveals beautifully colored layers, thanks to fillings such as prawns, prosciutto, egg salad, tomato, peppers and mozzarella. One thing is a constant – plenty of mayonnaise.