Trelew (pronounced Tre-leh-ew) is a commercial, industrial, and service hub that contains the region's main airport. Its biggest attractions are its paleontology museum (with the largest dinosaur fossils in the world on exhibit) and its proximity to the Punta Tombo reserve (though both can also be reached on day trips from Gaiman and Puerto Madryn). Otherwise, the city has little to recommend it: its mediocre hotels are notoriously overpriced, and aside from rental-car firms its tourism infrastructure is far less organized than Puerto Madryn's. If you come in the second half of October you can watch part of the Eisteddfod, a Welsh literary and music festival first held in Patagonia in 1875.
Trelew was founded in 1886 as a result of the construction of the now-defunct Chubut railway line, which connected the Chubut River valley with the Atlantic coast. The town is named after its Welsh founder, Lewis Jones (Tre means "town" in Welsh, and Lew stands for Lewis), who fought to establish this railroad.
The most Welsh of the Atlantic Patagonian settlements, sleepy Gaiman (pronounced Guy-mon) is far more charming than nearby Trelew and Rawson. A small museum lovingly preserves the history of the Welsh colony, and many residents still speak Welsh (although day-to-day communication is now in Spanish). A connection to Wales continues with teachers, preachers, and visitors going back and forth frequently (often with copies of family trees in hand). Even the younger generation maintains an interest in the culture and language.
Perhaps the town's greatest draws are its five Welsh teahouses (casas de té)—Ty Gwyn, Plas-y-Coed, Ty Nain, Ty Cymraeg, and Ty Té Caerdydd. Each serves a similar set menu of tea and home-baked bread, scones, and a dazzling array of cakes made from family recipes, although the odd dulce de leche–filled concoction is testament to Argentine cultural imperatives. Most teahouses are open daily 3–8 and charge about US$15 per person for tea (the spreads are generous enough to replace lunch or dinner, and you can usually take away a doggy bag of any cake you don't finish). Each establishment has its own family history and atmosphere, and there's healthy competition between them as to which is the most authentically Welsh.
Punta Tombo is home to one of the world's biggest colonies of Magellenic penguins; they come for the season to lay eggs and feed their newly hatched young. The park is also a great spot for observing other seabirds along with guanacos, seals, and hares.