https://whc.unesco.org/en/list/426

Palace of Westminster and Westminster Abbey including Saint Margaret’s Church

Westminster Palace, rebuilt from the year 1840 on the site of important medieval remains, is a fine example of neo-Gothic architecture. The site – which also comprises the small medieval Church of Saint Margaret, built in Perpendicular Gothic style, and Westminster Abbey, where all the sovereigns since the 11th century have been crowned – is of great historic and symbolic significance.

I have been to London: It is a cultural unescoworld heritage site.

https://whc.unesco.org/en/list/591

Thungyai-Huai Kha Khaeng Wildlife Sanctuaries

Stretching over more than 600,000 ha along the Myanmar border, the sanctuaries, which are relatively intact, contain examples of almost all the forest types of continental South-East Asia. They are home to a very diverse array of animals, including 77% of the large mammals (especially elephants and tigers), 50% of the large birds and 33% of the land vertebrates to be found in this region.

I havn't been to Tailand: It is a natural unesco worl heritage site.