Expo '70: What Osaka Built at Senri, and What Is Left

Japan acceded to the 1928 Paris Convention on International Exhibitions in February 1965 and was confirmed as host that September; the organising association launched a month later. What followed, in the words of the official Tower of the Sun site, was "five years and a month" of turning a hilly area north of Osaka into a world's fair.

The master plan was Kenzo Tange's and Uzo Nishiyama's, over 330 hectares of the Senri Hills. Tange invited twelve other architects to work inside it — Arata Isozaki designed the systems of the Festival Plaza, Kiyonori Kikutake the landmark tower. A Symbol Zone ran north to south with the Festival Plaza at its heart and, in the middle of that, the Tower of the Sun, from which walkways ran out to the north, south, east and west gates.

The scale is easier to grasp through the operational numbers than the architectural ones. The organisers describe an average daily electricity draw of 900,000 kW — comparable, they say, to the whole of Nara City. Parking covered 750,000 square metres and took 2,811,995 vehicles. There were 48,139 lost children.

The theme, "Progress and Harmony for Mankind", was not decorative. The organisers state that the exposition was designed to show not only technological progress but "various negative effects and problems that such progress may bring about" — environmental damage, loss of humanity — which for 1970 is a notably unsentimental brief.

Taro Okamoto's tower is the reason this site is still a destination rather than a lawn. Seventy metres tall, it stood at the centre of the Symbol Zone and pushed straight up through the Big Roof of the Festival Plaza — a building punctured by a sculpture, which was the point.

Inside it Okamoto built the Theme Space on three levels: an underground level for the past and the source of humanity, a surface level for the present and the dynamism of human contact, and the space frame above for a future in which people and technology are joined. The Tree of Life runs up the middle of it. Two companion towers, of Maternity and of Youth, stood alongside; they are gone.

It is enterable today, and it is the one part of a visit here you cannot improvise. Admission is by reservation only, with a minimum of one day's notice, and you are asked to arrive at least twenty minutes before your slot. Normal operating hours are 10:00 to 17:00. The fee is $4.51 (¥720) for adults and ¥310 for primary and middle-school children; a set ticket with the gardens is listed at ¥1,080 for adults.

One discrepancy worth knowing before you buy: that ¥1,080 set does not reconcile with the park's own revised gate price of ¥450 — ¥720 plus ¥450 is ¥1,170. Either the set ticket is a genuine saving of ¥90 or one of the two official pages had not caught up with the April 2026 revision when we read them in Q3 2026. Buy at the counter and ask which applies.

Admission to the Natural Culture Garden and the Japanese Garden together is $2.82 (¥450) for high-school age and above, effective 1 April 2026, and free for middle-school children and younger. Groups of 20 to 199 pay ¥360 each and groups of 200 or more ¥330; school groups enter free, guides included. The park announced the revision on 30 January 2026, which means a great deal of what is published elsewhere about the price of this park is now wrong.

Opening hours are 09:30 to 17:00, with the last admission thirty minutes before closing. It closes every Wednesday — or, when a Wednesday is a public holiday or a substitute holiday, on the next weekday instead — and over the new year. There are two exceptions worth planning around: from 1 April to 2 May, and throughout October and November, it does not close at all. Those are the cherry-blossom and autumn-colour windows, and the park is being explicit that it does not intend to be shut during them.

The EXPO'70 Pavilion is a separate $3.14 (¥500), free for middle-school children and below with a guardian, ¥400 for groups of 20 to 199 and ¥350 for larger ones, and ¥400 for holders of the park's all-pass. It is the surviving steel pavilion from the fair, registered as a national tangible cultural property, and its standing exhibition asks the question this whole page circles: where did all those pavilions go?

Parking, if you drive, starts at ¥410 for up to two hours on a weekday and runs to ¥1,100 for four to 24 hours, with weekend rates roughly half again as high. Getting there without a car means the Osaka Monorail, and the pass note above matters: only the Osaka Itami Airport edition of the Amazing Pass covers the monorail section and opens this park at all.

Almost nothing, is the honest answer, and that was the plan from the start: a world's fair is a temporary city. Almost all the pavilions were demolished after September 1970. What remains on the site is the Tower of the Sun, a section of the roof structure Tange designed for the Festival Plaza, the EXPO'70 Pavilion, and the landscape itself, which has had fifty-five years to grow into something that no longer reads as a construction site.

One survivor left the site by a longer route. The international art museum pavilion, designed by Kiyoshi Kawasaki, was reused as the building of the National Museum of Art, Osaka until March 2004, when the museum moved downtown and reopened in November 2004 on Nakanoshima — where it still is. So an Expo '70 building housed one of the city's major collections for three decades after the fair that built it had closed. The museums page covers where that collection lives now, and the Nakanoshima page covers the island it moved to.

Expoland, the amusement park inside the fair — about 172,500 square metres over six themed districts — is also gone. The commercial life of the site since 1970 has been a long series of things built on it and then replaced, which is its own kind of answer to a theme about progress.

Osaka held a second world exposition in 2025, not at Senri but on Yumeshima, a reclaimed island in Osaka Bay on the opposite side of the city. It ran from 13 April to 13 October 2025 — 183 days, exactly as in 1970 — with 158 countries and regions and seven international organisations taking part, against 77 countries in 1970.

The attendance figure is where it gets interesting, and where the archetype of this page repeats itself. The organisers publish two numbers side by side: a total of 29.02 million visitors, and 25.58 million excluding accreditation-pass holders — that is, excluding the staff and participants who passed through the gates every day. Press coverage generally reported the smaller figure. Neither is wrong; they count different things, and anyone comparing 2025 with 1970 needs to say which one they are using. Against 64,218,770 in 1970, both are less than half.

What became of the Yumeshima site afterwards is, at the time of writing, a story told largely by architectural and news outlets rather than by a primary source we could read. The reported outcome is that dismantling of Sou Fujimoto's Grand Ring began in December 2025, with roughly 200 metres of it — including a walkable section of the roof — retained on the island for a planned municipal memorial park, and timber from the dismantled sections auctioned off or shipped north for reuse in public housing. We are flagging that as reported rather than verified: unlike the 1970 figures above, we could not confirm it against an official page in Q3 2026, and a plan announced is not a park built.

Which is the useful comparison to end on. Fifty-five years after the first exposition, the surviving fragment of the second one is being planned at about 200 metres of a ring, and the surviving fragment of the first is a 70-metre tower that people book a slot to walk inside. The thing that lasts is rarely the thing that was engineered to last.

This is a half-day, not an hour, and it is a long way north of everything else a visitor does in Osaka — the site is in Suita, on the Osaka Monorail, not in the city centre. Treat it the way you would treat a day trip.

Book the Tower of the Sun first, because it is the only element that can sell out and it needs at least a day's notice. Then build the rest around the slot: the EXPO'70 Pavilion for the fair itself, the Japanese Garden for what the landscape became, and the lawns in between, which are where the scale of the original site finally lands.

Go on a day the park is open. Wednesday is the closed day for most of the year, and the two open-every-day windows are April into early May and the whole of October and November — which exist because of the blossom and the autumn colour, so they are also the busiest. Check the closure rule before you travel: a Wednesday public holiday moves the closure to the next weekday rather than cancelling it.

• Adult gate ¥450, children through middle school free, revised 1 April 2026
• Tower of the Sun ¥720 adult, ¥310 school-age, reservation required at least one day ahead, 10:00–17:00
• EXPO'70 Pavilion ¥500 adult, ¥400 with the park's all-pass
• Park 09:30–17:00, last entry 16:30, closed Wednesdays except in the open-daily windows
• Only the Osaka Itami edition of the Amazing Pass includes both the monorail section and free entry here