What are the most worthwhile things to do in Hong Kong on a first visit?

The geopark is the city's strongest claim to something geologically unique. Its columns are rhyolite — silica-rich and pale — rather than the dark basalt that forms the famous column fields elsewhere in the world. They average about 1.2 meters in diameter, with individual columns reaching 3 meters, and the formation spreads across roughly 100 square kilometers on land and under the sea, taking in High Island inside Sai Kung East Country Park, Kau Sai Chau, Jin Island, the Ung Kong Group and the Ninepin Group. The rock dates from volcanic activity around 140 million years ago that built a caldera about 20 kilometers across. The High Island Formation was brought into the geopark in 2009, and the whole park was accepted into the Global Geoparks Network on 17 September 2011.

The second day belongs to performance and ritual rather than skyline. Yueju — Cantonese opera — was inscribed on UNESCO's Representative List of the Intangible Cultural Heritage of Humanity in 2009, at the fourth session of the Intergovernmental Committee under decision 4.COM 13.27, on a nomination from China. UNESCO describes it as a form rooted in the Cantonese-speaking south, blending Mandarin operatic tradition with the Cantonese dialect, scored for strings and percussion, with elaborate costume and face paint and a male lead expected to both sing and fight, using staged combat drawn from Shaolin martial arts. In some rural communities it fuses with ceremonial religious practice as Shengongxi.

Hong Kong keeps its own heritage register alongside the international one. The first Representative List of the Intangible Cultural Heritage of Hong Kong was announced on 14 August 2017 by the Leisure and Cultural Services Department and holds 20 items, drawn from a wider territory-wide inventory of 480. Three of the 20 are things you can encounter directly as a visitor: the Hong Kong-style milk tea making technique, herbal tea, and sek pun, the basin feast of the walled villages.

The contrast is the point. Central's towers stand on reclaimed flatland at the foot of a ridge, and within an hour's travel the same territory turns into country park, with columnar cliffs dropping straight into open water off Sai Kung. The columns are pale enough that in strong afternoon light the sea stacks of the Ung Kong Group read almost white against the water.

Country park status, not tourism policy, is what has kept the geopark's coastline intact — High Island sits inside Sai Kung East Country Park, which is why the columns stand above undeveloped shoreline rather than behind a resort. It also means there is no gate, no ticket office and no single visitor center at the heart of the formation: access is by boat or by a long walk, and the sites are managed as protected countryside rather than as an attraction.

• Day one — Sai Kung and the geopark. Boat trips to the Ung Kong Group and the Ninepin Group leave from Sai Kung town; the sea arches and column stacks are the payoff.
• Day two — Cantonese opera and the urban heritage list. Yueju has been on UNESCO's Representative List since 2009; the Hong Kong list adds the milk tea technique and sek pun as living practices rather than museum pieces.
• Day three — Lantau and the harbor. The Tian Tan Buddha at Ngong Ping and a crossing of Victoria Harbour cover the two images most people arrive with.

Geopark boat operators cancel in rough seas, and from June to October the Hong Kong Observatory's record shows an average of nearly 15 tropical cyclone warning signal days across those five months, with August alone averaging 0.80 days at Signal No. 8 or higher — enough to cancel all ferry and outlying island services. The geopark's rock platforms are uneven and partly tidal. Cantonese opera performance schedules are concentrated around festival dates rather than running nightly, so a specific performance needs planning well before arrival.

The Hong Kong when-to-visit question in this group sets out the rainfall and typhoon-signal figures that decide whether the geopark day is realistic; the food question picks up the milk tea and herbal tea entries on the Hong Kong heritage list.