Jakob did Lübeck and the Works of Le Corbusier. He would like to have a second opinion on Chandigarh.

That one looks good to me. However, Immeuble locatif à la Porte Molitor and Chapelle Notre-Dame-du-Haut de Ronchamp appear a bit offset. Shape is perfect, but not exactly aligned with the element on the background map.

I will fix them tomorrow using a different map

Thanks to meltwaterfalls for adding the Rietveld Schröder House and Bremen.

And to Catoplayer for Guimaraes and Tower of Hercules, both with a bunch of POIs.

And added from the set by mmarquez:

Historic Town of Guanajuato and Adjacent Mines
Sian Ka'an
Historic Centre of Morelia
Historic Monuments Zone of Querétaro

Thanks to Jakob for the Bauhaus sites + POIs

Thanks to meltwaterfalls, we now have:
Petäjävesi Old Church
Old Rauma
Sammalahdenmäki
Fortress of Suomenlinna
Verla Groundwood and Board Mill
High Coast / Kvarken Archipelago

And more from the set by mmarquez:
Tequila (here zone 2 has incorrect official coordinates on the UNESCO website)
Aqueduct of Padre Tembleque
Uxmal
Caves of Yagul and Mitla
Whale Sanctuary of El Vizcaino
Rock Paintings of the Sierra de San Francisco
Zacatecas

And a bunch more;
Desembarco del Granma National Park (c) Protected Planet
San Pedro de la Roca Castle Els
Bialowieza Forest (c) Protected Planet adjusted
Nesvizh meltwaterfalls
Mir Castle meltwaterfalls
Struve Geodetic Arc meltwaterfalls (he reports finding possibly the smallest component ever: "the one in Jekabils is a circle with a radius of 80cm so 2m²")
Cienfuegos Els
Alejandro de Humboldt NP (c) Protected Planet
San Miguel de Allende Miguel Marquez
Luis Barragán House and Studio Miguel Marquez
Campeche Miguel Marquez
Tlacotalpan Miguel Marquez
Monarch Butterfly Biosphere Reserve Miguel Marquez
Central University City Campus of the UNAM Miguel Marquez
Medieval City of Rhodes Els
Sanctuary of Asklepios at Epidaurus Els

Yesterday's batch:
Studley Royal Park (c) Historic England
Stonehenge and Avebury (c) Historic England
Canterbury (c) Historic England
Maritime Greenwich (c) Historic England
Tower of London (c) Historic England
Saltaire (c) Historic England
City of Bath (c) Historic England
Durham Castle and Cathedral (c) Historic England
Royal Botanic Gardens, Kew (c) Historic England
Ironbridge Gorge (c) Historic England
Blenheim Palace (c) Historic England
Jodrell Bank Observatory (c) Historic England
Olympia Els
Acropolis Els (very tiny core zone)
Žatec – Landscape of Hops meltwaterfalls
Stone Spheres of the Diquís Miguel Marquez
Cocos Island Miguel Marquez
Archipiélago de Revillagigedo Miguel Marquez
Franciscan Missions in the Sierra Gorda Miguel Marquez
Kraków Jakob F.
Centennial Hall Jakob F.
Paquimé Miguel Marquez
Hospicio Cabañas Miguel Marquez
Popocatepetl monasteries Miguel Marquez
Archaeological site of Philippi Els
Delos Els
Corfu Els

(special thanks to meltwaterfalls for disentangling those by Historic England)

Maritime Greenwich: I haven't been there myself, but there's a tile with the UNESCO WHC logo on the sidewalk in front of the West Gate (entrance into the grounds of the Old Royal Naval College, where also the Tourist Information is). It is here: 51°28'55.7"N 0°00'31.3"W.

Just a couple I did yesterday, some with ChatGPT help for conversion
Schokland (c) Rijksdienst voor het Cultureel Erfgoed (converted)
Vilnius Historic Centre
Modernist Kaunas
Kernave Archaeological Site
Historic Centre of Riga
Pythagoreion and Heraion of Samos

If a mapper could have a look at Curonian Spit for a second opinion, as it is not fully clear to me: I read the official map like the Lithuanian part includes a marine area in the core zone, and once the spit crosses the border into Russia, it becomes a different national park and its borders follow the coast line only?

Yep! Looks like this https://commons.wikimedia.org/wiki/File:Maritime_Greenwich_World_Heritage_Site_plaque.png
Will add.

Yep I agree, in the nomination dossier it has this text, which corresponds to your interpretation:

Buffer zone: on the Russian part of- aquatory of the Baltic Sea and of the Curonian Lagoon within 1 km from the coast line

OK, I will map it then! Protected planet has half of it already